An analyzer apparatus comprises: a photometric unit including a plurality of types of light-emitting elements arranged at different positions and configured to selectively irradiate a reactive region with light having different center wavelengths, and an area sensor captures an image of a predetermined image capturing range including the irradiated reactive region; a color plate arranged in the image capturing range; and a processor configured to calculate a concentration of a detection target substance based on a measurement value corresponding to luminance data of the reactive region extracted from the image, extract correction luminance data of the color plate from the image, and correct the measurement value with the correction luminance data, wherein the processor changes an extraction region for the correction luminance data according to a type of the light-emitting element that emits the light.