To provide a connector inter-board for connection wherein adjustment of impedance is easy, fixing of two boards is not required to keep the interval constant, a structure is simple, and crosstalk decreases.

Ground plates 8, 8 at each plug side of plug connectors 2, 3 at both upper and lower portions are soldered to each upper and lower boards 9, 9 respectively, by which the plug connectors at both upper and lower portions are mounted on each upper and lower board, respectively. A receptacle connector 1 is engaged with one of the plug connectors at both upper and lower portions, then the other is engaged with the receptacle connector. In this case, projected portions 7c, 7c provided at insulators 7, 7 at each plug side of the plug connectors at both upper and lower portions are inserted into a slot 4b, and the ground plates at each plug side are inserted between ground plates 6, 6 on both receptacle sides and are pressure-welded. Since each bend 5b, 5b at both upper and lower sides of each signal contact 5 is resiliently brought into contact with each pad of each board, both boards are connected.