To resolve the complication of beam main reinforcements and prevent an anchorage failure and a shear failure from occurring in a column/beam junction.

A PCa beam member 1 has a nearly U-shaped cross section at least in a prescribed zone toward the inside of the member from an end face, and beam lower main reinforcements 3 protruded in the horizontal direction from the end face are bent upward at the length positions not exceeding the center line of a column member 5 in an installed state. The PCa beam members 1 are suspended between the column members 5 on the upper end sections of the column members 5. Beam end lower reinforcing main reinforcements 6 structurally connecting the beam lower main reinforcements 3 are arranged in the range between the opposite nearly U-shaped cross sections astride the column members 5. Positions near the end sections of the beam end reinforcing lower main reinforcements are set to hinge occurrence positions at an earthquake, then concrete is filled in the column/beam junction to integrally connect the column member 5 and the PCa beam members 1.