PURPOSE: To prevent the disconnection of a lead wire by a simple structure by forming irregularities on a base part surface whereto a round pin terminal is soldered for the purpose of fixing.

CONSTITUTION: In a base plate 12, base parts 12a and 12c are formed on the two places on the outer side of a supporting part 12b. A different-level part 12d is formed on the base part 12a, and the same different-level part is formed also on the base part 12c. A solder part 10 is formed on the base part 12a surface on which the different-level part 12d is formed, and the solder part 10 has a shape along the surface of the base part 12a to engage with the base part 12a surface. A solder part 11 to be formed on the base part 12c is also formed into a shape so as to engage with the base part 12c surface. Consequently, the rotation of round pin terminal 8 and 9 can be restrained because the solder parts 10 and 11 on the bases 12a and 12c are engaged with the base part surfaces respectively even the fitting between the round pin terminals 8 and 9 and the hole of the base plate 12 is loosened due to heating, etc., in soldering to make the round pins 8 and 9 rotatable.