This paper discusses cutting performance of the cutter jointly equipped with super high pressure water jets for mortar blocks when the parameters such as traversing rate and preset depth of cut were variously changed.
　The maximum jet pressure and the maximum flow rate used in the performance were 1900 kgf/cm2, 48l/min respectively. Throughout the experiments, actual volume of cut, cutting resitance and relationships among them were mainly investigated.
　It is revealed tha volume of cut by the cutter has increased about 42% than that by jets alone if only little mechanical power, which corresponds to 0.5% of jets' power, had added to the jets' power.