PURPOSE: To prevent traffic accidents by forming a key cylinder and a cam face to provide an operation path, a reverse path and a return path so that a key is again turned to ON by stopper walls then can be turned to LOCK when the key is inserted and turned to ON and returned to LOCK.

CONSTITUTION: A casing 11 and a cover 13 are provided on a steering lock device 10, a key cylinder 16 with a flange section 10 is rotatably arranged in the hole 14 of a housing case 12. A cam face 30 is formed on a rotary member 23 operation-connected to the key cylinder 16, an operation path 31, a reverse path 32 communicated to it, and a return path 33 communicating them are provided. A bulkhead 39 is provided between a side wall 38 perpendicularly formed to the second stopper wall 36 and the third stopper wall 37 on the LOCK side and the operation and reverse paths 31 and 32. The key rotation to the LOCK position can be surely recognized by a driver.