A medical image processing device comprising: an input processing unit (53, 56, 58) for performing an input process of a first color image signal; a color information obtaining section (72, 83, 85, 87) for obtaining two or more pieces of color information from the first color image signal; and a processor for performing a first process for increasing, within a first angle changing region including a first center line, a difference between coordinates in a first observation area and coordinates in a second observation area in a feature space that is a two-dimensional color space formed by the two or more pieces of color information, the first observation area being located on one side of the first center line, the second observation area being located on the other side of the first center line wherein the processor performs a second process for increasing, within a second angle changing region including a second center line that is different from the first center line, a difference between the coordinates in the first observation area located on one side of the second center line and coordinates in a third observation area located on the other side of the second center line in the feature space, and the second angle changing region is set to be greater in size than the first angle changing region, wherein in the first to third observation areas (B, C, A), coordinates corresponding to objects having different specific features respectively are distributed, there is a first distance D1 between an average value of the first observation area and an average value of the second observation area, there is a second distance D2 between the average value of the first observation area and an average value of the third observation area, and the second distance D2 is greater than the first distance D1, wherein the feature space is a B/G and G/R space. an input processing unit (53, 56, 58) for performing an input process of a first color image signal; a color information obtaining section (72, 83, 85, 87) for obtaining two or more pieces of color information from the first color image signal; and a processor for performing a first process for increasing, within a first angle changing region including a first center line, a difference between coordinates in a first observation area and coordinates in a second observation area in a feature space that is a two-dimensional color space formed by the two or more pieces of color information, the first observation area being located on one side of the first center line, the second observation area being located on the other side of the first center line wherein the processor performs a second process for increasing, within a second angle changing region including a second center line that is different from the first center line, a difference between the coordinates in the first observation area located on one side of the second center line and coordinates in a third observation area located on the other side of the second center line in the feature space, and the second angle changing region is set to be greater in size than the first angle changing region, wherein in the first to third observation areas (B, C, A), coordinates corresponding to objects having different specific features respectively are distributed, there is a first distance D1 between an average value of the first observation area and an average value of the second observation area, there is a second distance D2 between the average value of the first observation area and an average value of the third observation area, and the second distance D2 is greater than the first distance D1, wherein the feature space is a B/G and G/R space.