An IC card includes a frame of a rectangular border-shape, a printed circuit board, and one pair of shells. The printed circuit board is disposed on an interior portion of the frame and equips an electronic component. The one pair of shells cover the area surrounded by the frame with both faces of the shells, and constitute an outer shell of the IC card. One of the shells has a plurality of intermittent bent pieces on a periphery thereof. The bent pieces face an edge portion of the frame. The bent pieces establish one pair of hook pieces which protrude from a plate thickness surface (a flat side) on a front end portion thereof. Ultrasonic vibration is applied to a front end portion of the bent pieces while an edge portion of the frame is subjected to pressure, joining the bent pieces to the frame.