An organism information acquisition device is provided with an imaging part which images a user's hand opened and the user's hand bent to acquire a first image and a second image respectively; a dark line extraction part which extracts dark lines from the first image and the second image; a dark line element feature extraction part which extracts the darkness and width of the dark lines extracted by the dark line extraction part from the first image and the second image; and a surface information judgment part which extracts the dark lines being surface information relating to the hand on the basis of the darkness of the dark line in the first image, the deepness of the dark line in the second image, the width of the dark line in the first image, and the width of the dark line in the second image.