To construct a building with a wall type frame structure in a short time and in a low cost, by assembling a plurality of steel forms and placing concrete to form columns, wall faces, the upper slab, etc., of a room and further reusing the disassembled steel forms.

A steel form constituting a room is composed of respective four forms of the side forms 13a, 13b in which the space-adjusting forms 13h are inserted, and a middle form 13c and supported by hydraulic cylinders with casters so as to be vertically movable through posts 15. And an external form 13d at the veranda side and an external form at the corridor side are fitted through the forms 13e of columns and beams and the distance from the forms of the adjacent room or the wall thickness is regulated by spacers 36, 37. Then, concrete is placed and cured with heat by a heater sent in the inside to form columns, beams, wall faces, and the upper face slab. Thereafter, the steel forms 13a, 13b, 13c are disassembled and removed from an opening 28 to reuse them for the upper floor. Accordingly, a wall type frame structure can be constructed in a short time and a low cost.