To reproduce an image having fine printing density and rich in gradation on photographic paper without making the cost of a device rise.

This exposure device is provided with an LUT 32 converting inputted image data (8-bit data) of respective dots constituting the image into the outputted image data (12-bit data) of a gradation value in accordance with the color developing characteristic of the photographic paper, a data generation part 33 generating N pieces of outputted image data corresponding to the outputted image data of one dot when it is assumed that N is an integer ≥2, and an exposure part 7 exposing the photographic paper so that N dots corresponding to N pieces of outputted image data are formed on the photographic paper so as to be deviated to at least either of a main scanning direction and a subscanning direction. The data generation part 33 generates N pieces of outputted image data consisting of two or more kinds of data so that the gradation corresponding to the outputted image data of one dot may be reproduced on the photographic paper by entire N dots formed corresponding to N pieces of outputted image data.