A gloss determination device includes: an image acquiring unit that acquires a parallelly polarized image obtained by photographing an object illuminated by first polarized light through a polarizing filter which passes a polarized component polarized in a same direction as a polarization direction of the first polarized light, and a perpendicularly polarized image obtained by photographing the object illuminated by second polarized light through a polarizing filter which passes a polarized component polarized in a perpendicular direction to the polarization direction of the second polarized light; a differential image producing unit that produces a differential image indicating differences in brightness between the parallelly polarized image and the perpendicularly polarized image; and a gloss determining unit that determines a gloss condition of the object based on the differential image.