An abutment member 4 of a first hinge member A1 is pressed against a cam member 8 of a second hinge member A2 by a coiled spring 6. By this, an interval between an enlarged diameter portion 31 of an insertion member 3 of the first hinge member A1 and a connecting plate portion 72 of the second hinge member A2, is restricted to a predetermined interval. In other words, an interval between the end faces 31a, 72a of the enlarged diameter portion 31 and the connecting plate portion 72 is restricted to a predetermined interval. A friction member 10 composed of an elastic material such as a rubber is disposed between the end faces 31a, 72a. The thickness of the friction member 10 in the opposing direction of the end faces 31a, 72a is larger than the interval between the end faces 31a, 72a.