To provide a folding bicycle frame which secures sufficient rigidity as a front triangular frame at the time of running, as difficult with a folding bicycle according to the conventional technique, and which allows simple and quick folding and assembly of the body without use of any particular tool.

A frame of a folding bicycle is configured so that the front parts of rear wheel supporting frames 2 and 3 to bear the rear wheel 12 at the tail are borne 17 by the upper of a head pipe 1, and the forefront of a seat frame 6 to support a saddle 14 at the tail is shaft supported 18 by the lower part of the head pipe 1, and the part near the center where the frames 2 and 3 and the one 6 intersect is shaft supported rotatably by an intersecting rotary shaft 15. Between the foremost part of the rear wheel supporting frame 2 and the intersecting rotary shaft 15, a hinge part 4 is furnished which can bear the frames 2 and 3 being divided into two with possibility of being folded freely and can fix the frames 2 and 3 straight.