A cartridge case includes a case main body, a tape reel that includes a hub in the shape of a bottomed-cylinder and is rotatably enclosed inside the case main body, and a locking member on whose base part ring-shaped first teeth are formed, which is energized toward an inner surface of a base plate of the hub, is enclosed within the case main body so as to be capable of moving in a direction toward and away from the base plate, and restricts rotation of the tape reel. The tape reel includes a plurality of arc-shaped convex parts that are disposed on a circle about an axis of the hub on the inner surface of the base plate and support the locking member that has moved toward the base plate. Second teeth that engage the first teeth are formed on an upper part of at least one of the convex parts. A contact surface that contacts edges of the first teeth without engaging the first teeth is formed on an upper part of at least one of the convex parts.