To prevent a filling fault consequent on the deaeration is not conducted, on the occasion of compression molding of a molded article of cement mortar.

A recess groove 31a is formed in the outer peripheral surface 31A of a core tool 31 in a lower die 3 constituting a molding apparatus, along the circumferential direction of the surface, so as to reduce the area of a liquid film existing on a sliding face between the core tool 31 and a form 32.