The invention provides a showcase having at least two glass doors, a first door being fastened to a front ferrule and a second door being fastened to a rear ferrule, each of the ferrules moving along a respective rail, said locking device comprising a lock for locking the two doors together, wherein the showcase includes a locking device comprising a slider mounted to move in said front ferrule transversely relative thereto, and having a rotor of the lock installed thereon, wherein said rear ferrule includes an opening that comes into line with said rotor in a position for locking the two doors together, and that is suitable for receiving a bolt mounted at the end of said rotor, and wherein said slider includes a relatively flat face plate coming substantially flush with said ferrule in the locked position of said doors.