A connector is constructed such that the front half portions of a pair of connector housings each accommodating a terminal are coupled with each other, and are locked and connected together by means of a pair of locking members. This connector comprises a detecting spacer locked and connected to one of the pair of connector housings by means of another pair of locking members and a lock-releasing portion provided on the other connector housing for releasing locking between the detecting spacer and the one of the pair of connector housings when the other connector housing is properly coupled with the one of the pair of connector housings.