According to the embodiment, an optical inspection method includes: acquiring an image by capturing the image, using light from a surface of an object, which passes through a wavelength selection portion configured to selectively pass light components of a plurality of predetermined wavelengths different from each other, the image sensor including color channels configured to discriminately receive the light components of the plurality of predetermined wavelengths, performing color count estimation processing configured to estimate the number of colors based on the intensity ratio of the color channels that have received the light in each pixel of the image, and performing scattered light distribution identification processing configured to identify a scattered light distribution as BRDF from the surface of the object based on the number of colors or surface state identification processing configured to identify a state of the surface of the object based on the number of colors.