PURPOSE: To make the connection easy and to attain the automation and cost reduction, by inserting a pin insulator having conductors to a fitting hole of a cylinder and connecting both ends of the conductor to a printed board and a head.

CONSTITUTION: The pin insulator 10 to which a bare conductor 11 is inserted along a shaft center, is inserted and kept in a fitting hole 4 through upper and lower part of a cylinder 1. A lower projection 12 of the conductor 11 is soldered to the printed board 3 and an upper projection 13 is connected to a head 2. The lower end of the insulator 10 is formed as taper 16, several latch projections 17 are provided at the outer circumference to make the insertion to the hole 4 easy, and the tolerance of size of the insulator 10 to the hole 4 is relieved. Thus, the connection of the conductor 11 is made easy and the insertion of the insulator 10 is automated.