Machining method and cutting device

The invention provides a processing method and a cutting device, which can restrain poor processing. The processing method is a processing method for a package substrate in which a plurality of intersecting division lines are set, the processing method having the following steps: a dirt confirmation step (1001) in which a holding table is imaged by a camera to confirm dirt on the holding table, the holding workbench is provided with a tool withdrawal groove of the cutting tool in a region corresponding to the division predetermined line, and suction holes for sucking and holding the packaging substrate are respectively formed in the regions divided by the tool withdrawal groove; a cleaning step (1003) for cleaning the holding table by supplying a cleaning liquid to the holding table when the dirt is confirmed by the dirt confirmation step (1001); a holding step (1004) in which the package substrate is held by a holding table; and a cutting step (1005) of cutting the package substrate held by the holding table