1. A multicolor vector image processing device, comprising: a data analysis unit to analyze vector image data including line information defining an outline and area color information defining a first color and a second color respectively for two areas adjacent to each other across the outline; a detection unit to detect a boundary pixel through which an outline passes based on the line information; a longitudinally passing determination unit to determine whether or not the outline passes longitudinally through the boundary pixel; and a coloring unit to sequentially fill each pixel on a scan line, wherein the coloring unit calculates a color of a target pixel based on the area color information and fills the target pixel with the calculated color when the target pixel is a boundary pixel through which an outline does not pass longitudinally, the coloring unit calculates a color of a target pixel based on the area color information, fills the target pixel with the calculated color, and changes a reference filling color from the first color to the second color defined for the target pixel when the target pixel is a boundary pixel through which an outline passes longitudinally, the coloring unit fills a target pixel with the reference filling color when the target pixel is not a boundary pixel.