PROBLEM TO BE SOLVED: To provide a cap for a medicinal bottle that can prevent the upper face contamination of a rubber plug of the medicinal bottle from the initial use until the last use when using a medical solution in the medicinal bottle many times.SOLUTION: A cap 10 is mounted to a bottle mouth of the medicinal bottle with the bottle mouth blocked with a rubber plug. A top face plate 12 of the cap 10 is bored with a through hole 13. A fixing cap member 20 including the top face plate 22 and a circumferential body part 21 is formed with a fixing cylinder part insertable in the through hole 13, at the center part of the lower face, and held in a locked state to the cap 10 by this fixing cylinder part. A fitting cap member 30 is formed with a locking cylinder part 31 detachably engaged with the through hole 13 of the cap 10. The fixing cap member 20 is formed with a circular groove part 24 fittable to the locking cylinder part 31.
