To provide concrete form for a building, for use in forming a concrete skeleton of a steel reinforced concrete structure or a steel encased concrete structure, which is low in cost, easy to produce, high in strength, excellent in durability, and easy to assemble.

The concrete form is molded by extruding polypropylene, and consists of a flat panel portion 1 and side-edge and intermediate reinforcing rib portions 2m and 2e which are integrally molded with the panel portion at both longitudinal side edges and widthwise intermediate portions of the panel portion in a manner extending in parallel with each other. Further, the reinforcing rib portions 2e and 2m have their edges opened outward 4.