Abstract: The invention discloses a hinge device for mounting a toilet seat cover, comprising an upper stand, a lower stand and a locking pin. The lower stand is provided with chutes while the upper stand is equipped with inserts matching the chutes, and the inserts and the chutes are matched with each other, by which the upper stand can be inserted into the lower stand along the set direction. The rod of the locking pin is mounted on the lower stand, the inner end of the rod extends to a limiting stand on the lower side of the upper stand, the inner end of the rod is provided with a limiting stopper. By this design, a safety apparatus is added for the separation of the upper stand from the lower stand so that the utility model is safer.