To realize an optical fiber connector coupled or decoupled by simple insertion and removal operation without applying ferrule connecting force to other elements (package board or back panel), the optical connector comprises a first housing (33); a second housing (34); a third housing (36) slidably housed within the second housing; a first engage mechanism (37, 38) provided between the second and third housings, for engaging these two housings when the first and third housings are not coupled; a second engage mechanism (39, 40) provided between the first and third housings, for engaging these two housings when the first housing is coupled to second and third housings; a first release member (41) provided for the first housings, for releasing the first engage mechanism when the third housing is engaged to the first housing; and a second release member (42) provided for the second housing, for releasing the second engage mechanism when the second housing is coupled to the third housing or the first housing is decoupled from the second and third housings. Further, to allow the optical connector to be preferably applicable to a plug-in connector with the smallest possible dimensions and with the highest possible package density, a novel connector floating structure, a novel slidable ferrule supporting structure, a strong optical plug connecting mechanism, a reliable optical plug or jack insertion structure, a cleanable and replaceable connector jack, etc. are also disclosed.