A frame joint connecting connection portions to each other, the connection portions being arranged in frame members of a vehicle, includes an inner peripheral wall including abutment surfaces, the abutment surfaces being arranged in the one connection portion and crossing with each other in the radial direction, tapered surfaces being arranged in the other connection portion and facing the inner peripheral wall, an expansion collar movable in the radial direction so as to abut on the inner peripheral wall, and a fastener keeping fitting of the expansion collar in a state where the expansion collar abuts on the inner peripheral wall.