To record a track of strong light for necessary time while exposure of a dark part is settled within an appropriate range.

An image processing apparatus 3 includes: an averaging synthesis section 4 to which a plurality of images acquired by leaving time intervals are inputted, and which generates an averaged synthesis image by performing weighted average processing of pixel values of pixels to which the respective images correspond; a high luminance image generation section 5 which makes a weighted average ratio of largest values in the pixel values of the pixels to which the plurality of images correspond be larger than the weighted average value ratio of the other pixel values to perform weighted average processing, so as to generate a high luminance image; a synthesis ratio setting section 6 which sets a synthesis ratio of the averaged synthesis image generated by the averaging synthesis section 4 and the high luminance image generated by the high luminance image generation section 5 so that a ratio of the high luminance image becomes larger as the pixel value of the high luminance image becomes larger; and an image synthesis section 7 for synthesizing the averaged synthesis image and the high luminance image according to the synthesis ratio which is set by the synthesis ratio setting section 6.