PURPOSE: To firmly arrange anchor steel rods of a PC beam without use of large columns and easily construct it.

CONSTITUTION: Main reinforcing steel rods 5 of the lower end beam protrudes from the end face of a half PC beam 2 and L-shaped anchor steel rods 12 are connected to the front end. A pair of half PC beams 2 are oppositely arranged at both sides of the defined space 11 of concrete columns 3. The L-shaped anchor steel rods 12 are raised up within the defined space 11 by the columns. The main reinforcing steel rods 14 of the upper end beam are laid down without joints, between the half PC beams of both sides. A full PC beam can be used instead of the half PC beam 2. In this case, the anchor steel rods are jointed to the main reinforcing rods of the upper end in these going-down direction.