The present invention provides a laser processing apparatus by which it is possible to properly form through-grooves along all division lines of a workpiece. The laser processing apparatus includes: achuck table (10) that holds a packaged wafer (201); a laser beam applying unit (20) that applies a pulsed laser beam to the packaged wafer (201); an X-axis moving unit for moving the chuck table (10)in an X-axis direction; an imaging unit (50) that images the packaged wafer (201); and a control unit (60). The chuck table (10) has a transparent or semi-transparent holding member (11) and a lightemitting body. The control unit (60) includes: an imaging instruction section (61) that causes the imaging unit (50) to image the packaged wafer (201) while the pulsed laser beam is being applied to the packaged wafer (201); and a determination section (62) that determines the processed state of a through-groove from a picked-up image obtained according to an instruction by the imaging instructionsection (61).