A cosmetic box includes a first part and a second part which is pivotably connected to the first part and the second part can be swung away from the first part to expose the cosmetic items received in the first part. The second part includes a ring-shaped positioning portion and a frame with a mirror is pivotably engaged with the ring-shaped positioning portion. A collar is mounted to the ring-shaped positioning portion and includes a stop which stops the frame when not in use such that the frame closes the central hole of the collar so as to form a disk-like cosmetic box.