A laser annealing apparatus (1) according to an embodiment includes a laser oscillator (4) configured to generate a laser beam (L), a floating-type conveying stage (3) configured to float and convey a workpiece (W) to be irradiated with the laser beam (L), and a beam profiler (7) configured to measure a beam profile of the laser beam (L). The floating-type conveying stage (3) includes a conveying surface (3a) opposed to the workpiece (W), and a bottom surface (3b) on the side opposite to the conveying surface (3a). The beam profiler (7) is positioned below the bottom surface (3b) of the floating-type conveying stage (3). The floating-type conveying stage (3) includes a detachable part (12) in a part of it. An opening (S) is formed by detaching the detachable part (12) from the floating-type conveying stage (3), the opening (3) extending from the conveying surface (3a) to the bottom surface (3b). The beam profiler (7) is configured to measure the beam profile of the laser beam (L) through the opening (S).