Abstract: Disclosed is an autofluorescence quenching device that: quenches only autofluorescence without quenching fluorescence that is originally desired to be observed in a tissue section in a short time; does not emit noise in various wavelength regions; is capable of controlling a temperature increase; can be used repeatedly with a simple operation; and can stably quenches autofluorescence. The autofluorescence quenching device for a sample includes: a sample placement unit; and an irradiation unit mounted on the sample placement unit. The sample placement unit includes: a flat plate; one or more sample placement recesses each in which a sample is to be placed and which are provided in the flat plate; and a cooling means for cooling the sample placement recesses. The irradiation unit includes one or a plurality of white LED illuminations placed above the respective sample placement recesses.