A hinge device of a portable terminal couples a body and a folder of the portable terminal and enables rotation of the folder with respect to the body. The hinge device includes a cylindrical hinge housing having an open end, a closed end, and a suspending block that projects from a peripheral surface of the cylindrical hinge housing and extends longitudinally between the open end and the closed end; a hinge shaft having a disk and an angular block projecting from the disk, disposed along a hinge axis, the disk being housed in the cylindrical hinge housing and the angular block protruding through the open end of the cylindrical hinge housing; a hinge cam, disposed outside the cylindrical hinge housing, having a concave block disposed along the hinge axis in opposition to the angular block of the hinge shaft, to engage in a sliding motion in conjunction with the angular block; and a conical compression coil spring, disposed between the closed end of the cylindrical hinge housing and the disk of the hinge shaft, to press the hinge shaft against the hinge cam. The conical compression coil spring is compressible into a plane, so that the space required for installing and assembling the hinge device in the portable terminal can be reduced. When the hinge housing is combined with the folder of a foldable terminal, the hinge cam is combined with the body of the foldable terminal. Combining the hinge housing with the folder and the hinge cam with the body obviates the need for an axis of a conventional hinge cam, which combines the hinge device with the body, thus enabling the miniaturization of the hinge device and a portable terminal using the same.