A stopper 50 is fixed to an optical connector 10, and the optical connector 10 is accommodated in an opening section 21 of a housing 20. The housing 20 is engaged with the stopper 50 so as to be displaceable with respect to the stopper 50 by a predetermined amount in a direction of inserting the optical connector 10 to a receptacle, and the stopper 50 is biased rearward by a coil spring 40 with respect to the housing 20. The free end of a clip piece 15 is placed on the free end of a latch piece 14 of the optical connector 10, and the free end of the clip piece 15 is placed on an inclination surface 23a at the front end of a concave section 23 formed on an inner wall surface of the opening section 21. At the time of detachment from the receptacle, the housing 20 is displaced in a direction to be pulled out against the biasing force of the coil spring 40. Accordingly, the clip piece 15 and the latch piece 14 are pushed down by the inclination surface 23a to release the lock of the latch piece 14. The detachment from the receptacle can be made in one motion.