PURPOSE: To remove excessive water when the concrete cast into a form is subjected to centrifugal molding by providing a filter material composed of a porous material capable of preventing the passage of fine particles to the inner perpheral surface of the weir plate directly in contact with the molded product in a centrifugal molding concrete form under tension.

CONSTITUTION: PS steel rods are set to the inside of a split form 1 and two parts 1a, 1b are clamped. A concrete transport pipe is inserted in the form 1 to cast concrete into the form 1 and the form 1 is rotated on drive rollers 11 and concrete is uniformly moved in the circumferential direction of the form 1 by the centrifugal force generated by the rotation of the form 1 to form a cylindrical concrete pile having a uniform wall thickness without using a core. By this constitution, excessive water in concrete is moved to the outer periphery of the form by the centrifugal force generated by the rotation of the form 1 to penetrate into a filter element 8 and further guided to water purifying facilities.