To eliminate fear of being unintentionally ignited by easily rotating in the releasing direction since a stopper being a lock member projects from a body.

This operation lock mechanism 8 has a lock slider 8a displaceably installed on the top end side of a piezoelectric unit 4, a conductive member 8b vertically movably installed in the lengthwise direction of the piezoelectric unit 4 and a lead wire covering separating part 8c capable of supplying electric power with the conductive member 8b. The conductive member 8b has a sliding projection 8b1 arranged so as to slide in parallel in the vertical direction of the piezoelectric unit 4 and mutually engaging by extending in the horizontal direction between the lock slider 8a and an earth member 8e. Thus, since engagement of the lower end of the slider 8a and the sliding projection 8b1 of the conductive member 8b is not released as far as the lock slider 8a is slid in the direction for going away from a windshield, discharge is not performed toward a gas blowout nozzle 10 from a discharge terminal 5 so that ignition cannot be performed.