An imaging device and an imaging method are provided that are capable of, for example, accurately recognizing the state of blood circulation of an examinee when the examinee undergoes surgery. An imaging device includes: an excitation light source configured to irradiate an examinee with excitation light to excite a fluorescent dye administered to the examinee； a capturing unit configured to obtain a fluorescent image by capturing fluorescence generated from the fluorescent dye； a pixel value measurement unit configured to measure, over time, a pixel value of each pixel in a predetermined region of the fluorescent image； a gradation conversion unit configured to perform gradation conversion of the pixel values measured by the pixel value measurement unit to a predetermined number of gradations； a gradation image generation unit configured to generate a gradation image based on the pixel values subjected to the gradation conversion by the gradation conversion unit； and an image display unit configured to display the gradation image.
