To provide a connector having high contact reliability transmitting a high frequency signal at a high speed, and using an inexpensive flat-plate like object to be connected in which a ground line and a ground layer positioning on the sides opposite to each other are not electrically connected.

The flat-plate like object 100 to be connected includes a signal line S and a ground line G on its one side, and has a ground layer GL discontinuous with the ground line which is formed on the other side. This connector includes an insulator 20 in and from which the flat-plate like object to be connected can be inserted and removed, a signal contact 50 having contact parts 54, 55 electrically connected to the signal line by making contact with it, and a ground contact 40 having fork like contact parts 44, 45, 46, 47 to hold the object to be connected between the ground line and the ground layer while each making contact with them.