There is provided a method of determining whether or not a result of a processing process of a laser processing apparatus is acceptable including a laser processing step of applying a laser beam to predetermined processing regions of a workpiece held on a chuck table, thereby performing a piercing process on the workpiece, an image capturing step of capturing images of all the processing regions while moving the image capturing unit and the workpiece relatively to each other, a detecting step of detecting regions where light is not transmitted through the workpiece among the processing regions in the image captured in the image capturing step, and a determining step of determining that the laser processing apparatus needs to be readjusted if the regions where light is not transmitted through the workpiece is equal to or more than the predetermined quantity.