Wall saw having a locking device (41). A saw blade flange (25) of the wall saw is adjustable by the locking device (41) between a locked state and an unlocked state, wherein, in the locked state, the saw blade flange (25) is connected to the drive spindle (33) for rotation therewith, and, in the unlocked state, is adjustable in relation to the drive spindle (33). In the unlocked state of the saw blade flange, the drive spindle is blocked in the direction of rotation of the saw blade and is designed to be rotatable about the axis of rotation in a counter direction directed counter to the direction of rotation.