diff --git a/main.py b/main.py
index 09f7907..23375a0 100644
--- a/main.py
+++ b/main.py
@@ -10,6 +10,7 @@ from datetime import datetime, timedelta
 import emoji
 import ephem
 import pygame
+import pygame.gfxdraw
 import pytchat
 from playsound import playsound
 from pygame.locals import *
@@ -91,7 +92,6 @@ class Main:
         # 大月ヨヨコ
         jojoko: pygame.Surface = pygame.transform.scale (
                 pygame.image.load ('moon.png'), (200, 200))
-        jojoko.set_colorkey (pygame.Color (0, 255, 0))
 
         # 音声再生器の初期化
         pygame.mixer.init (frequency = 44100)
@@ -166,7 +166,7 @@ class Main:
             cls.draw_bg (screen, bg_day, bg_evening, bg_night, bg_grass,
                          kita, jojoko,
                          sunrise_start, sunrise_end, sunset_start, sunset_end,
-                         sun_alt)
+                         sun_alt, moon_alt, moon_days_old)
 
             # 左上に時刻表示
             for i in range (4):
@@ -296,7 +296,7 @@ class Main:
                                      bg_grass, kita, jojoko,
                                      sunrise_start, sunrise_end,
                                      sunset_start, sunset_end,
-                                     sun_alt)
+                                     sun_alt, moon_alt, moon_days_old)
 
                         chat_item.author = {'name':     'ゴートうひとり' if goatoh_talking else '伊地知ニジカ',
                                             'id':       '',
@@ -333,14 +333,17 @@ class Main:
             sunrise_end:        datetime,
             sunset_start:       datetime,
             sunset_end:         datetime,
-            sun_alt:            float) \
+            sun_alt:            float,
+            moon_alt:           float,
+            moon_days_old:      float) \
     -> None:
         sunrise_centre: datetime = (
                 sunrise_start + (sunrise_end - sunrise_start) / 2)
         sunset_centre: datetime = (
                 sunset_start + (sunset_end - sunset_start) / 2)
 
-        jojoko: pygame.Surface = jojoko_original.copy ()
+        jojoko: pygame.Surface = cls.get_jojoko (jojoko_original,
+                                                 moon_days_old)
 
         dt: datetime = datetime.now ()
 
@@ -358,10 +361,19 @@ class Main:
         else:
             bg_evening.set_alpha (0)
 
+        if sunrise_start <= dt < sunset_end:
+            jojoko.set_alpha (255 - 255 / 15 * abs (moon_days_old - 15))
+        else:
+            jojoko.set_alpha (255)
+
         screen.blit (bg_evening, (0, 0))
 
-        # TODO: 緑を塗ってヨヨコを缺かす．
-        # pygame.draw.arc (jojoko, (0, 255, 0), 
+        if -10 <= moon_alt < 40:
+            y = ((CWindow.HEIGHT / 2 + 100)
+                 - (CWindow.HEIGHT / 2 + 200) / 30 * moon_alt)
+            screen.blit (jojoko, jojoko.get_rect (center = (400, y)))
+
+            screen.blit (bg_grass, (0, 0))
 
         if -10 <= sun_alt < 40:
             y = ((CWindow.HEIGHT / 2 + 100)
@@ -370,6 +382,32 @@ class Main:
 
             screen.blit (bg_grass, (0, 0))
 
+    @classmethod
+    def get_jojoko (
+            cls,
+            jojoko_original:    pygame.Surface,
+            moon_days_old:      float) \
+    -> pygame.Surface:
+        jojoko: pygame.Surface = jojoko_original.copy ()
+
+        jojoko.set_colorkey ((0, 255, 0))
+
+        for i in range (200):
+            if 1 <= moon_days_old < 7:
+                pygame.gfxdraw.bezier (jojoko, ((0, 100 + i), (100, 180 * moon_days_old / 7 - 80 + i), (200, 100 + i)), 3, (0, 255, 0))
+            elif moon_days_old < 14:
+                pygame.gfxdraw.bezier (jojoko, ((0, 100 + i), (100, 180 * moon_days_old / 7 - 80 + i), (200, 100 + i)), 3, (0, 255, 0))
+            elif moon_days_old < 15:
+                pass
+            elif moon_days_old < 22:
+                pygame.gfxdraw.bezier (jojoko, ((0, 100 - i), (100, 180 * (moon_days_old - 15) / 7 - 80 - i), (200, 100 - i)), 3, (0, 255, 0))
+            elif moon_days_old < 30:
+                pygame.gfxdraw.bezier (jojoko, ((0, 100 - i), (100, 180 * (moon_days_old - 15) / 7 - 80 - i), (200, 100 - i)), 3, (0, 255, 0))
+            else:
+                jojoko.fill ((0, 255, 0))
+
+        return jojoko
+
 
 if __name__ == '__main__':
     Main.main (sys.argv, len (sys.argv))
diff --git a/moon.png b/moon.png
index 80c0c90..bbd399e 100755
Binary files a/moon.png and b/moon.png differ