In a duplex optical connector plug 10, first and second tip portions of first and second engagement latches 77a, 77b enter first and second recessed hole portions of first and second guide protrusions 36a, 36b formed at front end portions of first and second plug frames 20a, 20b. When the first and second engagement latches 77a, 77b elastically deform and the first and second tip portions lift upward, upwardly inclined surfaces of the tip portions contact downwardly inclined surfaces of the first and second recessed hole portions. Thus, upward lifting of the first and second tip portions is prevented by the recessed hole portions. Therefore, the first and second elastic portions of the first and second engagement latches 77a, 77b are elastically deformed downward and sufficiently pressed downward.