To provide a laser scanning microscope and an operation method thereof.

There are provided a laser scanning microscope including at least two detection channels and an operation method thereof. The laser scanning microscope includes at least one beam splitter (ST) which splits sample light at a split ratio different from 50:50, and includes at least one of detectors (DE) which are adjusted with different amplification factors in the case where a split ratio in the detection channels is 50:50, or includes an optical attenuator in at least one detection channel in the case of the same light split ratio.