An electric steering lock device, comprising: a cam arranged to allow forward rotation and reverse rotation inside of a frame; a lock member which, while following a cam face of the rotating cam, is arranged to be movable forward and backward between a locked position at an advancing end and an unlocked position at a retreating end, and a position detection device that detects that the lock member is positioned at the unlocked position is arranged between the frame and the lock member, wherein the cam face comprises: a locking and unlocking segment for moving the lock member between the locked position and the unlocked position; a lock release position segment in which the lock member is held in the unlocked position; and an unlock stopping segment that is constructed to have the change ratio of a cam lift amount that is larger than the change ratio of the cam lift amount in the lock release position segment, wherein the locking and unlocking segment, the lock release position segment, and the unlock stopping segment are arranged in the order of the locking and unlocking segment, the lock release position segment, and the unlock stopping segment, wherein a change ratio of the cam lift amount to a rotation angle of the cam in the lock release position segment is constructed to be zero, characterised in that the unlock stopping segment is a segment to operate the position detection device via the lock member, the change ratio of the cam lift amount in the unlock stopping segment is set to operate the position detection device via the lock member. a cam arranged to allow forward rotation and reverse rotation inside of a frame; a lock member which, while following a cam face of the rotating cam, is arranged to be movable forward and backward between a locked position at an advancing end and an unlocked position at a retreating end, and a position detection device that detects that the lock member is positioned at the unlocked position is arranged between the frame and the lock member, wherein the cam face comprises: a locking and unlocking segment for moving the lock member between the locked position and the unlocked position; a lock release position segment in which the lock member is held in the unlocked position; and an unlock stopping segment that is constructed to have the change ratio of a cam lift amount that is larger than the change ratio of the cam lift amount in the lock release position segment, wherein the locking and unlocking segment, the lock release position segment, and the unlock stopping segment are arranged in the order of the locking and unlocking segment, the lock release position segment, and the unlock stopping segment, wherein a change ratio of the cam lift amount to a rotation angle of the cam in the lock release position segment is constructed to be zero, characterised in that the unlock stopping segment is a segment to operate the position detection device via the lock member, the change ratio of the cam lift amount in the unlock stopping segment is set to operate the position detection device via the lock member. a locking and unlocking segment for moving the lock member between the locked position and the unlocked position; a lock release position segment in which the lock member is held in the unlocked position; and an unlock stopping segment that is constructed to have the change ratio of a cam lift amount that is larger than the change ratio of the cam lift amount in the lock release position segment, wherein the locking and unlocking segment, the lock release position segment, and the unlock stopping segment are arranged in the order of the locking and unlocking segment, the lock release position segment, and the unlock stopping segment, wherein a change ratio of the cam lift amount to a rotation angle of the cam in the lock release position segment is constructed to be zero, characterised in that the unlock stopping segment is a segment to operate the position detection device via the lock member, the change ratio of the cam lift amount in the unlock stopping segment is set to operate the position detection device via the lock member.