To prevent, with a simple structure, damage on a component such as a conductive contact at the time of operation of an actuator, an actuator pinching a signal transmission medium by being moved to a connection acting position facing a wiring board is provided with a protective projection protruding toward the wiring board with the actuator being moved to the connection acting position. With this, a gap between the actuator and the printed wiring board is covered with the protective projection from outside, the components such as conductive contacts disposed inside the gap between the actuator and the printed wiring board are prevented from being in contact with a nail of an operator.