When each value of luminance signals of three primary colors in the primary video signal is less than the output lower limit value, in short, when the gradation level is negative, the negative gradation level of the present primary color is, in accordance with its magnitude, in other words, in accordance with the absolute value of the negative gradation level, replaced with positive gradation levels of other two primary colors. Therefore, in accordance with A VIDEO SIGNAL CONVERTER of this invention, even when the primary video signal includes a signal value having a negative gradation level, in short, even when one or more of each signal value of RGB is below the output lower limit value, a color according to the combination of those gradation levels (a combination of each level of primary colors (RGB)) can be reproduced (displayed) by a display means.