A filter device including a red filter unit, a green filter unit, a blue filter unit and at least one of a yellow filter unit, a cyan filter unit and a magenta filter unit is provided. Red light, green light and blue light are produced when white light passes through the red filter unit, the green filter unit and the blue filter unit. In the CIE1931 color space coordinate, a triangle color space is formed through joining the points representing the red, green and blue light. Moreover, yellow light, magenta light and cyan light are produced when white light passes through the yellow filter unit, the magenta filter unit and the cyan filter unit. In the CIE1931 color space coordinate, the minimum distance from the points representing the yellow, magenta and cyan light to the edge of the triangle is not exceeding in 0.03.