PURPOSE: To provide the exposure device of the color video printer which reduces the necessary cost of a back light accompanying an increase in the size of a print screen and uniformly backlights an R, a G, and a B panel.

CONSTITUTION: This device consists of the R, G, B LCD panels 31-33 which are installed above a support case 30 without any interference with mutual lights, a light reflecting member 35 which is installed movably to the right and left in the support case 30 below the R, G, and B LCD panels 31-33 and supports a light source 34 and converges the light of the light source 34 only on a corresponding liquid panel among 31-33 for irradiation, and a driving means which moves the light source support and light reflecting members to the right and left.