A modular jack is composed of: a base connector installed on a printed circuit board, and a socket connector with a parallel crank mechanism at an extremity thereof, the parallel crank mechanism being slidably connected to the base connector and switching an upper housing between a raised state and a lowered state. When the upper housing is laid toward the front side of the socket connector, the socket connector can be housed inside the casing and both faces of the upper housing, the socket housing, and the base housing are made in a flat plate-like shape. This contributes to height reduction in the modular jack. The socket connector is configured such that, when the upper housing is pulled out from a side face of the casing and raised outside the casing, a plug can be electrically connected to the socket connector.