It is aimed to attain compatibility between a size reduction, a thickness reduction of a portable terminal and the ensuring of an energizing force is attained. An upper case 2 is coupled with a connecting portion 4 to proceed in a predetermined direction with respect to a lower case 3. Two cases 2, 3 have a close state in which they are overlapped mutually and an open state in which the upper case 2 is extended by moving in a predetermined direction. One end of a coil portion 33A is fixed to a second hole 46 and the other end of the coil portion 33A is fixed to a third hole 50, and the connecting portion 4 has a torsion coil spring 33 that applies an energizing force to two cases 2, 3 such that the cases 2, 3 are brought into the close state or the open state. The coil portion 33A is arranged in a clearance 56 that is formed by a part of two cases 2, 3 when the two cases oppose to each other in the moving direction, and the clearance 56 is arranged in a vicinity on a predetermined direction with respect to the third hole 50 in the close state.