A wire line connector includes a main contact body is provided with an electrical connection trench into which an insulated wire is compressed at the rear end, a protrusion that engages with a housing and prevents disconnection in the middle portion, and a contact portion at the front end. The portion of the contact portion on the rear end side forms parallel walls and the portion on the front end side forms protruding parallel walls in such a manner that the outer surfaces of the protruding walls and the inner surfaces of the parallel walls make contact with each other when the two connector portions are connected. The housing is provided with a step to be engaged with the protrusion for preventing disconnection of the main contact body, and an engaging hole and an engaging protrusion which prevent disconnection when the housing is connected with another housing.