In a video coding device, an intra prediction unit 11 generates a predicted block, based on an adjacent reconstructed image. A intra first chroma prediction mode coding unit 12 codes an intra prediction mode of a first chroma component based on an intra prediction mode of a luma component. A intra second chroma prediction mode coding unit 13 codes an intra prediction mode of a second chroma component depending on the intra prediction mode of the first chroma component.