A board mating connector in which a signal contact unit and a ground contact unit are interlocked, the board mating connector comprising: a signal contact unit which has one side in contact with a signal electrode of a board and is electrically connected to the signal electrode; a ground contact unit which has one side in contact with a ground electrode of the board and is electrically connected to the ground electrode; and a dielectric unit which is disposed between the signal contact unit and the ground contact unit, wherein the signal contact unit includes a housing which has a housing insertion hole of which one side is open, a contact portion which has a contact portion insertion hole of which the other side is open, and the ground contact unit includes a first ground portion and a second ground portion, the first ground portion has a first ground hollow portion, the other side of the second ground portion is partially inserted into the first ground hollow portion and has a second ground hollow portion, the dielectric unit includes a first dielectric portion which is disposed between the housing and the first ground portion and a second dielectric portion which is disposed between the connection portion and the second ground portion, characterized in that, the signal contact unit further includes a connection portion which has the other end inserted to be movable along an inner side of the housing insertion hole and one end inserted to be movable along an inner side of the contact portion insertion hole, the second ground portion is relatively moved while in contact with the first ground portion so as to be coupled to and interlocked with the connection portion through the dielectric unit, and when the second ground portion is moved in a direction of the first ground portion or in a direction opposite to the direction of the first ground portion, the connection portion is moved together with the second ground portion by the second dielectric portion in a direction in which the second ground portion is moved. a signal contact unit which has one side in contact with a signal electrode of a board and is electrically connected to the signal electrode; a ground contact unit which has one side in contact with a ground electrode of the board and is electrically connected to the ground electrode; and a dielectric unit which is disposed between the signal contact unit and the ground contact unit, wherein the signal contact unit includes a housing which has a housing insertion hole of which one side is open, a contact portion which has a contact portion insertion hole of which the other side is open, and the ground contact unit includes a first ground portion and a second ground portion, the first ground portion has a first ground hollow portion, the other side of the second ground portion is partially inserted into the first ground hollow portion and has a second ground hollow portion, the dielectric unit includes a first dielectric portion which is disposed between the housing and the first ground portion and a second dielectric portion which is disposed between the connection portion and the second ground portion, characterized in that, the signal contact unit further includes a connection portion which has the other end inserted to be movable along an inner side of the housing insertion hole and one end inserted to be movable along an inner side of the contact portion insertion hole, the second ground portion is relatively moved while in contact with the first ground portion so as to be coupled to and interlocked with the connection portion through the dielectric unit, and when the second ground portion is moved in a direction of the first ground portion or in a direction opposite to the direction of the first ground portion, the connection portion is moved together with the second ground portion by the second dielectric portion in a direction in which the second ground portion is moved.