To provide the constructing method of a building frame by a composite member by overcoming the difficulties of the ensuring of workers in building- frame construction works.

Column reinforcement cages 10 are disposed in upright at regular intervals while wall bars 24 are arranged, and the forms of a column 1, beams 2, 3 and walls 4, 5 are assembled. A prefabricated deck 7 is installed between beam forms 25, beam cages 13, 20 are mounted into beam forms, a PC- constructed balcony 8 and a corridor 9 are set up on the beam cages 20 in the girder direction, and concrete for the column 1, the beams 2, 3, the walls 4, 5 and a floor slab 6 is placed.