A housing connection structure comprising a ferrule housing having a distal end portion and a housing receiving portion of a connector, wherein the distal end portion of the ferrule housing is detachably coupled to the housing receiving portion, the ferrule housing accommodating and supporting a plurality of ferrules (10A, 10B) to which terminals of optical fiber cables are attached such that distal ends of the ferrules (10A, 10B) protrude from a distal end surface of the ferrule housing, and the connector incorporating optical circuit terminals to be connected to the ferrules (10A, 10B), wherein the ferrule housing comprises: an engaging protrusion provided to protrude from a distal end portion of one outer side surface of the ferrule housing in an outward direction perpendicular to the one outer side surface; a ferrule urging spring attached to a base end portion of the ferrule housing to urge the ferrules (10A, 10B) in a direction protruding from the distal end surface of the ferrule housing; and a lock arm provided on an opposite outer side surface on a side opposite to the one outer side surface, the lock arm having a flexible arm extending in a direction from a base end side of the ferrule housing toward a distal end side of the ferrule housing and a connector engaging portion provided on a distal side outer surface of the flexible arm and being a recess, wherein the housing receiving portion comprises; a chamfered pivot portion configured such that a corner portion at a distal end of one inner side surface of the housing receiving portion that faces the one outer side surface is chamfered; an engaging recess configured in a recessed manner and located on the one inner side surface at a distance inwardly from the distal end so that the engaging protrusion is engageable with the engaging recess; and a housing locking portion being a protrusion for locking the connector engaging portion and being provided on an opposite inner side surface that faces the opposite outer side surface to lock the connector engaging portion, and wherein the distal end portion of the ferrule housing is coupled to the housing receiving portion such that, from a state in which the one outer side surface of the ferrule housing is in contact with the chamfered pivot portion of the housing receiving portion in an inclined manner, the ferrule housing is pivoted about the chamfered pivot portion serving as a fulcrum so that the one outer side surface overlies the one inner side surface, the engaging protrusion is engaged with the engaging recess, and the connector engaging portion is locked at the housing locking portion. an engaging protrusion provided to protrude from a distal end portion of one outer side surface of the ferrule housing in an outward direction perpendicular to the one outer side surface; a ferrule urging spring attached to a base end portion of the ferrule housing to urge the ferrules (10A, 10B) in a direction protruding from the distal end surface of the ferrule housing; and a lock arm provided on an opposite outer side surface on a side opposite to the one outer side surface, the lock arm having a flexible arm extending in a direction from a base end side of the ferrule housing toward a distal end side of the ferrule housing and a connector engaging portion provided on a distal side outer surface of the flexible arm and being a recess, wherein the housing receiving portion comprises; a chamfered pivot portion configured such that a corner portion at a distal end of one inner side surface of the housing receiving portion that faces the one outer side surface is chamfered; an engaging recess configured in a recessed manner and located on the one inner side surface at a distance inwardly from the distal end so that the engaging protrusion is engageable with the engaging recess; and a housing locking portion being a protrusion for locking the connector engaging portion and being provided on an opposite inner side surface that faces the opposite outer side surface to lock the connector engaging portion, and wherein the distal end portion of the ferrule housing is coupled to the housing receiving portion such that, from a state in which the one outer side surface of the ferrule housing is in contact with the chamfered pivot portion of the housing receiving portion in an inclined manner, the ferrule housing is pivoted about the chamfered pivot portion serving as a fulcrum so that the one outer side surface overlies the one inner side surface, the engaging protrusion is engaged with the engaging recess, and the connector engaging portion is locked at the housing locking portion.