Malfunctions caused by dusts such as sands and the like in movement portions of a spark-voltage generation mechanism are reduced. The generation mechanism comprises an outer-box assembly in which a base piece, piezoelectric element, and anvil are disposed in line with the longitudinal axis, an axis-direction cam groove is formed thereon, an inner-box assembly in which a hammer that strikes the piezoelectric element and a hammer spring are housed, a cam hole is formed thereon, and a joint-case assembly that limits the stroke of the outer-box assembly over the inner box-assembly, generates a high-voltage pulse by series of operations where one-way-pressure force is applied with a hammer pin inserted into the hammer, the cam groove, and the cam hole to compress and release the hammer spring. The hammer strikes the piezoelectric element by releasing the compression force of the hammer spring, the operation mechanism is shielded with the joint-case assembly.

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