An object is to provide a laser dicing apparatus and a laser dicing method capable of speedily performing high-quality dicing without causing any working defect even in a case where wafers varying in thickness are supplied. The laser dicing apparatus is provided with a measuring device which measures thickness of a wafer W, a recording device which stores a database in which modified region forming conditions associated with different thicknesses of the wafer W are described, and a control device which controls the laser dicing apparatus by automatically selecting, from the database, on the basis of the thickness of the wafer measured by the measuring device, the modified region forming conditions corresponding to the measured thickness of the wafer W. The optimum modified region forming conditions are thereby automatically set, so that even in a case where wafers W differing in thickness are supplied, high-quality dicing can be speedily performed without causing a working defect.