A measurement data correction method is provided. A living organism is employed as a test sample, fluorescent light generated by excitation light from a fluorescent substance administered to the test sample is received by a light receiving component at a plurality of locations around the periphery of the test sample in a flat plane passing through an observation site of the test sample, and the method is employed for reconstruction of an optical tomographic image of the test sample along the flat plane passing through the observation site. The method includes: generating corrected measurement data, as measurement data to be used in reconstruction of an optical tomographic image along the flat plane passing through the observation site of the test sample, from an obtained first measurement data and an obtained first standardization measurement data using a defined correction coefficient.