A cellular terminal apparatus has a structure for folding an upper apparatus 2 and a lower apparatus 3 via a hinge portion 4. Printed circuit boards 5, 6 arranged in the upper apparatus 2 and the lower apparatus 3 are connected to each other by a flexible printed circuit board (FPC) 7 and a connection cable 8 passing inside the hinge portion 4. At the boundary between the hinge portion and the upper apparatus 2 and the lower apparatus 3, the space between the FPC 7, the connection cable 8, and the external case is filled by a seal packing 9 in such a manner that the FPC 7 and the connection cable 8 are separate from each other.