The present invention is a small-sized hinge device for connecting a first member and a second member rotating relatively to each other, such as a transmitter section and a receiver section of a twofold portable telephone, comprising a case body with baffle means mounted in one of the members, a fixed cam provided inside the case body, a shaft arrested by the case body with one end thereof passing through the fixed cam along its axial direction and the case body along its axial direction, an arresting body disposed in the other end of the shaft and attached to the other one of the members, a cam slider disposed to face the fixed cam and slide along an axial direction of the shaft with the rotation thereof arrested by the shaft, and a compression spring interposed resiliently between the cam slider and the arresting body.