PURPOSE: To improve assembling property and productivity by forming an operation electromagnet device and operation system part into an operation electromagnet unit, housing a control circuit unit, a stator part and in a base, then fixing a cover to the base, and fixing the units to the case.

CONSTITUTION: An operation electromagnet device 2 and an operation system part are housed as an operation electromagnet unit B straddled over the central large space 1A and the central small space 1B of a base 1, and a control circuit switch 18 and a control terminal 17 are housed as a control circuit unit E in the right space 1C of a case A. Further, the lead wires 3a, 3b of the operation electromagnet device 2, are connected and a needle part C having a movable contact 11 and a stator part D having a fixed contact 14 are contained in the left space 1D of the base 1, respectively. After the needle part C is connected to the operation system part by a pin 30 and housed in the base 1, a cover is fixed to the base 1, and they are fixed in the case A, Thus, assembling property and productivity can be enhanced.