A connector fitting body (1) is formed by tightening a bolt (4) arranged in a collar (6) of a first housing (2) into a nut (5) of a second housing (3). The bolt (4) includes a head (41) to contact an end surface of the collar (6) and a shaft. A base portion (42) of the shaft is linked coaxially to a tip side of the head (41), and a tip portion (43) of the shaft is linked coaxially to the base portion (42) of the shaft. An inner peripheral surface of the collar (6) has a base end inner peripheral surface (61) with the base portion (42) of the shaft arranged thereon and a tip inner peripheral surface (62) having a smaller inner diameter than the base end inner peripheral surface (61) and having the tip portion (43) of the shaft arranged thereon.