HOUSING CONNECTION STRUCTURE

A ferrule housing (20) accommodating a plurality of ferrules (10A, 10B) is provided with an engaging protrusion (24) protrusively formed at the tip on one outer surface (20c) of the housing (20), an energizing spring (25), and a lock arm (26) extending to an outer surface (20d) on the opposite side of the housing (20). A housing accommodation part (31) of a connector (30) is provided with a chamfer part (33) used as a fulcrum for rotational movement, an engaging recess (34) into which the engaging protrusion tightly fits, and a housing locking part for locking the lock arm. The ferrule housing is moved rotationally using the chamfer part as a fulcrum from a state in which the ferrule housing has one outer surface tilted so as to contact the chamfer part to such a state that the one outer surface overlaps one inner surface of the housing accommodation part, causing the engaging protrusion to fit tightly into the engaging recess and also causing the lock arm to be locked to the housing locking part. Wear in an area of the ferrule housing subject to sliding when the ferrule housing moves rotationally is prevented, and deterioration in coupling strength between the ferrule housing and the housing accommodation part and deterioration in alignment of the ferrule housing are prevented.