To provide a half-precast concrete member having strength enough to be applied to a large-sized floor board without causing the complication of labor for construction.

This half-precast concrete member comprises: a concrete plate in which a main reinforcement is embedded; a plurality of truss bars which are partially embedded in the concrete plate, and the rest of the bars are exposed at the top surface of the concrete plate; and a fiber-reinforced concrete plate which is coupled to an undersurface of the concrete plate.