An imaging device of the present invention, using image data that has been continuously read out at specified time intervals from an image sensor, generates dark image combination image data resulting from dark image combination using darker pixel data of each pixel of image data is generated, and bright image combination image data resulting from bright image combination using brighter pixel data of each pixel of image data, and difference output image data is generated from the bright image combination image data and the dark image combination image data. With the generated dark image combination image data as background image data and the difference output image data as light trace output image data, respective brightness is adjusted, and by subjecting each of the image data after adjustment to addition combination, it is possible to respectively independently adjust background brightness and light trace brightness.