To reduce costs of forms remarkably by molding a matrix-shaped pseudorock block using concrete of a small slump value by demolding instantly.

Each vibration mechanism is stopped, a press plate 41 is lifted, after an aggregate regulating frame being removed from the upper surface of a form 1, a concrete removing bar is made to travel from one end to the other of the upper surface of the form 1, and excess concrete 32 is scraped off from the upper surface of the form 1 and removed. A press mechanism is actuated again to bring down the press plate 41 to lift the lower surfaces of matrix-shaped pseudorock blocks B. Next, each vibration mechanism is stopped to lift the press plate 41, after a pallet 51 being fixed on the upper surface of the form 1, and a vibration table and the form are turned over. A transportation base is set under the pallet 51, after canceling the fixture of the form 1 to the vibration table, the vibration mechanism of the vibration table is actuated, and the blocks B are demolded.