To avoid a housing from being fitted obliquely.

First and second servo members 30 and 60 movable to a standby position and a fitting position are mounted to a housing 10. The first and second servo members 30 and 60 have first and second cam receivers 34 and 64 and the first and second cam receivers 34 and 64 are slid in contact with a cam follower 94 formed in an opposite-side housing 90, respectively, so that the opposite-side housing 90 is made closer to the housing 10. Moving directions of the first and second servo members 30 and 60 from the standby position to the fitting position are different from each other. The cam follower 94 is a shared cam follower that is shared by the first and second cam receivers 34 and 64. The first and second cam receivers 34 and 64 are then formed approximately symmetrical with respect to a width direction orthogonal with a fitting direction.