To provide a folding three-wheel bicycle which can be folded very rapidly when using a public transportation or bringing it in a main entrance or a veranda of a house, and occupies less space.

An X-shaped folding frame has a frame (2) for connecting a handlebar to a rear wheel, and a frame (3) for connecting a saddle and two front wheels thereacross so as to be turnable at the crossing position (8). A wire (12) is passed into the inside connection via a guide (13). The force obtained by a handlebar shaft (11) is transmitted by the wire (12). Steering can be realized by moving a tie rod (14) for turning the front wheels mounted on a front wheel part having a lean mechanism, and the X-shaped frame can be folded rapidly.