In one embodiment of the present invention, a signal conversion circuit is disclosed which is suitably used in a multiprimary liquid crystal display device, and a multiprimary liquid crystal display device having such a signal conversion circuit. A signal conversion circuit according to one embodiment of the present invention is for use in a multiprimary liquid crystal display device, and converts an input video signal to a multiprimary signal corresponding to four or more primary colors. When generating a multiprimary signal for displaying dark skin, the signal conversion circuit according to an embodiment of the present invention applies a conversion to the video signal so that a color difference Δu′v′=((u′−u60′)2+(v′−v60′)2) is 0.03 or less, the color difference Δu′v′ being defined by CIE1976 chromaticity coordinates (u′, v′) representing a chromaticity when the pixel is viewed from the frontal direction and CIE1976 chromaticity coordinates (u60′, v60′) representing a chromaticity when the pixel is viewed from a 60° oblique direction.