PURPOSE: To perform assembling easily and quickly, by inserting each component in the same direction in assembling each component.

CONSTITUTION: An opening section of a case member faces a bobbin support member 12 incorporated by inserting two bobbin members 10, the support member 12 is shifted in the same direction as the bobbin member 10 being inserted to the member 12, and the three components 18 put in together are inserted to a recess 19. In this case, a connecting pin is projected from a hols 17 through which the connecting pin is inserted, and then the assembly 18 inserted to a housing member 20 is fixed with a screw inserted from the outside of the housing member 20.