An ignition switch device is provided with a switching device 2 having a key hole 2a, and capable of being rotationally operated in a predetermined direction with an ignition key K inserted to start and stop the engine of an industrial machine, a case 3 covering the switching device 2 and formed with an insertion hole 3b allowing the key hole 2a to face the outside, a shutter 4 rotatable between a closed position where the insertion hole 3b of the case 3 is closed, and an open position where the insertion hole 3b is opened to allow the key hole 2a to face outside, and a protruding portion 7 formed within the range of rotation of the shutter 4 while protruding from the surface 3a of the case 3 and whose protruding end contacts the rear surface 4b of the shutter 4 while the shutter 4 rotates.