PURPOSE: To achive miniaturization as a whole by integrating a sub body and an auxiliary yoke by outsert molding to eliminate positional deviation between members composing the head.

CONSTITUTION: The center of an auxiliary yoke 40 is integrated with a sub body 47 concurrently serving as rear guide by outsert molding. A fitting through hole 40a of a plunger 46 formed on an auxiliary yoke 40, the mounting position of a post 41 and a guide hole 47b of a wire 49 formed on a guide 47a of the sub body 47 can be coincided in the relative positional relationship as designed.