To provide a connector with a new composition that generates little inserting force between connectors.

This connector has two or more housings 11, 12 jointed by a hinge 13 with a fixed interval to make them freely open and close. An opening and closing connector 10 whose electrical contact parts of terminals contained inside this housings 11, 12 are located inside these housing 11, 12 and a block connector 20 that is other connector of the opening and closing connector 10 and has a block state housing 21 whose electrical contact parts of terminals contained inside these housing 21 are located outside the housing 21 are provided. While the opening and closing connector 10 is in a closed state, both connectors 10, 20 are connected each other by inserting the block connector 20.