PURPOSE: To wash away cutting chips positively by providing a gas blowing mechanism, which blows the gas on the surface of a wafer so that washing liquid flows in the constant direction on the surface of the semiconductor wafer.

CONSTITUTION: A dicing device has a vacuum suction stage 25, which mounts a semiconductor wafer 16 that is a material to be processed, a rotating blade 37, which cuts the wafer 16, and a washing-liquid feeding mechanism, which feeds washing liquid 46 to the cutting part. Impellers 42, which send wind in the radial direction of the blade 37 by the rotation of the blade 37, are provided on both side surfaces of the blade 37. The wind is generated by the rotation of the blade 37 with a gas blowing mechanism comprising the impellers 42. The washing liquid on the surface of the wafer 16 forcibly flows in the constant direction by the action of the wind. Therefore, the washing liquid drifting on the surface of the wafer 16 flows to the outside of the wafer as the strong stream.