Abstract: An optical flux is radiated, which is focused at a measurement point in a specimen space, and a transmitted light amount is measured. A minute light absorption amount is measured from a transmitted light signal and a reference signal. While three-dimensionally scanning, a three-dimensional map in which light absorption amounts are represented by voxels (volume cells) is obtained. On this three-dimensional map, deconvolution processing with a light intensity distribution image in the vicinity of the measurement point being a convolution kernel is performed, so as to obtain a three-dimensional image of a specimen that is almost transparent in a non-dyed state.