PURPOSE: To enable the strength of the cement mold after its curing to be sufficiently kept, while the fluidity of cement is kept in good condition by providing the water-absorbing part absorbing the bleeding water from the cement in a form.

CONSTITUTION: A water-absorbing part 7 is formed by shaving a blocklike foamable plastic into a prescribed shape or bonding a plurality of platelike foamable plastic with an adhesive on the like, and is stuck firmly to the lower surface of a top plate 6 with the adhesive, etc. When cement material 10 is cast into a form 4 from the casting port 9 formed on the top plate 6 of the form 4, the moisture contained in the cement 10 rises in the curing, process of the cement and becomes bleeding water. Said water enters the inside through the air hole, etc. of the water-absorbing part 7 and is accumulated in a space 8. According to necessity, while the bleeding water accumulated in the space 8 is removed from the extracting port 12 of the top plate 6 by a syringe, etc., the cement is cured.