To reduce the adhesion of mortar to a blade body, to check the deterioration of cutting performance, and to make the properties of a cut surface improved by cutting semicured mortar by a cutting means in which blade bodies are installed intermittently in the longitudinal direction of an endless belt which moves around or in the circumferential direction of a rotary disk.

When an auxiliary cutting means is moved horizontally to follow a cutting means which is transferred by a traveling means, a roller cutter 4a rotates clockwise by the resistance of a substrate 1 and cuts the uncut part (m) of a mortar block while rotating and pushing it. Since the distance between blades of the cutter 4a is slightly narrower than the clearance between cut surfaces formed by cutting blades fixed intermittently, both outer surfaces of the cutter 4a contact the cutting surfaces, and cutting and separation can be done with the properties of the cut surfaces of the mortar block M improved.