To obtain a self-fluorescence image with an excellent S/N ratio generated from measuring object located at a remote site in biological tissue using fluorescence image acquisition method and equipment.

In the case that of self-fluorescence Kj generated from biological tissues 1 by irradiation of excitation light Le is taken by an image sensor 25 and the taken Kj is read out as an image, read-out frequency of the image sensor 25, area per pixel, total number of pixels, pixel binning number, read-out port number, exposure time, quantum efficiency, electronic multiplication factor and device temperature are set to meet the following formula to obtain images. RN+DN<0.22×P×H×G, herein RN: number of charge generated by exposure noise (determined by read-out frequency and area per pixel), DN: number of charge generated by dark noise (determined by read-out frequency, area per pixel, total number of pixels, pixel binning number, read-out port number, exposure time, quantum efficiency, electronic multiplication factor and device temperature), P: irradiation output (mW) of excitation light, H: quantum efficiency of imaging element and G: electronic multiplication factor of image sensor.