Vertically aligned carbon-nanotube (CNT) film is expected as a superior low contact thermal resistance material. The microscopic deformation behavior of CNT in contact is clarified by previous study, but the difference in the deformation behavior when changing the length of CNT is not clarified. The vertically aligned CNT film was brought into contact with a plano-convex lens, and the contact surfaces were observed using a laser microscope with both high resolution and wide field of view. We clarified the difference in the deformation behavior when changing the length of CNT by analyzing states of the contact surfaces under various contact pressures. In each length of CNT, the relation of the intensity of reflected laser of 2-beam interference and contact surface pressure was elucidated.