To provide a high voltage generating device for an electric discharge ignition device capable of reducing possibility of occurrence of damage on a mounting part in comparison with a conventional one by reducing stress added in mounting and demounting.

Mounting claws 51, 52 are integrally formed on both longitudinal side end parts of an outer housing 2. The mounting claw 52 is composed of a mounting part 53 extended from a side wall part of the outer housing 2 to a side part, a flexible part 54 extended from a tip end side of the mounting part 53 along the side wall part, and a claw 55 mounted on a tip end part of the flexible part 54. A corner part of a connection part with the mounting part 53, of the flexible part 54 is a chamfered part 56.