A tissue imaging system comprising: an imaging means (12, 34, 202) for creating an object image of an object with information of oxygen saturation of a blood vessel; a monitor image generating means (86, 86a) for generating a monitor image (93, 94) including the object image, and change information of said oxygen saturation; an area determining means (19, 87); and a display means (14, 204) for displaying said monitor image, characterized in that the area determining means (19, 87) is adapted to determine a specific area within said object image, said specific area being movable by following motion of said object, wherein said monitor image generating means (86, 86a) is adapted to generate a monitor image (93, 94) including change information of the oxygen saturation according to a part image included in said object image and located in said specific area, wherein said tissue imaging system further comprising: a location updating unit adapted to update a location of said specific area according to said motion of said object at each time of creating a frame of said object image; and a data acquisition unit adapted to acquire said oxygen saturation of said part image in said specific area when said specific area is updated, wherein said monitor image generating means (86, 86a) is adapted to generate a graph of said oxygen saturation changeable with time, and said monitor image (93, 94) includes said graph, wherein said location updating unit is adapted to extract a landmark point (100, 110) in relation to said object at each time of creating a frame of said object image, and to update said location of said specific area according to said landmark point (100, 110), wherein said location updating unit is adapted to determine a shift between plural frames of said object image created with a time difference according to said landmark point (100, 110), and to update said location of said specific area according to said shift, and wherein said landmark point (100, 110) is different from said specific area. an imaging means (12, 34, 202) for creating an object image of an object with information of oxygen saturation of a blood vessel; a monitor image generating means (86, 86a) for generating a monitor image (93, 94) including the object image, and change information of said oxygen saturation; an area determining means (19, 87); and a display means (14, 204) for displaying said monitor image, characterized in that the area determining means (19, 87) is adapted to determine a specific area within said object image, said specific area being movable by following motion of said object, wherein said monitor image generating means (86, 86a) is adapted to generate a monitor image (93, 94) including change information of the oxygen saturation according to a part image included in said object image and located in said specific area, wherein said tissue imaging system further comprising: a location updating unit adapted to update a location of said specific area according to said motion of said object at each time of creating a frame of said object image; and a data acquisition unit adapted to acquire said oxygen saturation of said part image in said specific area when said specific area is updated, wherein said monitor image generating means (86, 86a) is adapted to generate a graph of said oxygen saturation changeable with time, and said monitor image (93, 94) includes said graph, wherein said location updating unit is adapted to extract a landmark point (100, 110) in relation to said object at each time of creating a frame of said object image, and to update said location of said specific area according to said landmark point (100, 110), wherein said location updating unit is adapted to determine a shift between plural frames of said object image created with a time difference according to said landmark point (100, 110), and to update said location of said specific area according to said shift, and wherein said landmark point (100, 110) is different from said specific area. a location updating unit adapted to update a location of said specific area according to said motion of said object at each time of creating a frame of said object image; and a data acquisition unit adapted to acquire said oxygen saturation of said part image in said specific area when said specific area is updated, wherein said monitor image generating means (86, 86a) is adapted to generate a graph of said oxygen saturation changeable with time, and said monitor image (93, 94) includes said graph, wherein said location updating unit is adapted to extract a landmark point (100, 110) in relation to said object at each time of creating a frame of said object image, and to update said location of said specific area according to said landmark point (100, 110), wherein said location updating unit is adapted to determine a shift between plural frames of said object image created with a time difference according to said landmark point (100, 110), and to update said location of said specific area according to said shift, and wherein said landmark point (100, 110) is different from said specific area.