To provide a method of automatically and objectively determining the atomizing performance of an atomizing nozzle head without having contact with the atomized substance.

There is provided an apparatus pairing a laser beam emitting device and a sensor for measuring the attenuation of the laser beam. By arranging side by side a plurality of this paired apparatus, attenuation in one direction in a space can be measured, and the concentration in one direction can be calculated from the measured attenuation. By arranging a plurality of the mono-axial measuring apparatuses at varied angles, attenuation rates in a plurality of directions can be measured, and concentrations in a two-dimensional plane can be calculated from the attenuation rates in the plurality of directions. By spraying an atomized substance for the test use from a nozzle head and measuring the concentration of the atomized substance for the test use with the concentration measuring apparatus, the atomizing performance can be determined. The determination is automatically accomplished by decision logic as to the absence of a high concentration due to failure in atomization and the presence of a prescribed spraying range and spraying shape.