To enable release operation of a lock piece by a jig while miniaturizing a splitting connector.

In a locking protrusion 38 arranged on the side face of a sub connector 30, a groove 39 is formed, and on an engaging surface 26A of the lock piece 26 arranged on an inner wall of a housing part 12, a releasing protrusion 27 to be inserted into the groove 39 is formed so as to be protruded. Engagement with the locking protrusion 38 can be released by bending and deforming the lock piece 26 as pressing a guide face 27A of the releasing protrusion 27 in the groove 39 by the jig J. As a result, since the size of the lock piece 26 can be farther reduced than before, bending space for the lock piece 26 also can be reduced, thereby enabling the miniaturization of a housing body 11 as well as female and male connectors 10, 50.