To provide a connecting method requiring no connecting work of a beam connecting lower end reinforcement in a narrow beam-column joint part space surrounded and locked by the end face of a concrete part and having multiple column main reinforcements stood densely while allowing use of a non-timbering construction method in connection between precast concrete beams linearly facing each other for improving workability and facilitating hanging work of a precast concrete beam.

In concrete parts 2 in the mutually opposed end parts of both precast concrete beams 1, a plurality of slits 5 opened to the upper face and the end face in the concrete part are formed. In each of the slits 5 having a depth reaching the beam lower end reinforcement level, a lateral wide part 5a is formed in the end part. A reinforcement 8 having a knob engaged with the lateral wide part is dropped into the facing slit, and concrete 10 for the beam upper part and the beam-column joint part is placed after a beam upper end reinforcement 9 is arranged in the upper parts of both precast concrete beams.