Retaining projections are formed on and project outwardly in a right-left direction respectively from right and left side walls of a spacer. The retaining projections are used for achieving a provisionally-retained condition and a completely-retained condition of the spacer. When the side walls are elastically deformed, the retaining projections slide over respective retaining portions of a connector housing to thereby achieve the retained condition. The side walls which can be elastically deformed inwardly in the forward-rearward direction form portions of right and left outermost terminal passage holes, and therefore must hold respective metal terminals, respectively. Therefore, holding projections are formed on and project inwardly in the right-left direction respectively from the side walls. These terminal holding projections serve to hold the respective metal terminals in predetermined positions.