To improve adhesion between protectors and a housing without increasing machining cost, metal mold cost and material cost.

A locking portion 16 projecting in the wall thickness direction of the housing 6 is formed at each of the longitudinal ends 16 of the protectors 15a, 15b and 15c. By such a structure, the protectors 15a, 15b and 15c are jointed in a wedge driving manner to the housing 6 in a longitudinal end area. Therefore, even if a molding temperature is low, the adhesion between the protectors 15a, 15b and 16c and the housing 6 is improved, and the protectors 15a, 15b and 15c can be suppressed from being separated from the surface of the housing 6.