A connector-mounting construction has a bracket (10) with a mounting hole (12) and a to-be-locked plate (13) adjacent to the mounting hole (12). A connector (20) has an end configured for insertion through the mounting hole (12) and a flange (27) dimensioned contacting the rear surface of the bracket (10). An insertion groove (35) extends into the flange (27) parallel to a front surface of the flange (27). A metal lock (50) has an insertion portion (60) in the insertion groove (35) and a locking piece (51) projecting forward along a side of the connector (20). The locking piece (51) has at least one resiliently deformable locking projection (55) with a rearwardly facing locking surface (56) configured for locking edge forwardly facing edge (14) the to-be-locked plate (13) of the bracket (10) when the flange (27) of the connector (20) contacts the rear surface of the bracket (10).