An apparatus for displaying a shape of an insertion portion comprising: an insertion portion configured to be transformed; a plurality of attitude acquisition units which are disposed at a plurality of measurement points fixed to the insertion portion and each of which is configured to acquire acceleration applied to the respective measurement points and attitude information on attitudes of the respective measurement points in a resting state; a shape calculation unit configured to calculate the attitudes of each of the measurement points and relative positions of the measurement points to other of the measurement points, based on a position of each of the measurement points and each of the attitude information in the insertion portion; a movement determination unit configured to determine whether the measurement points move based on the acceleration; a movement period specification unit configured to specify a movement period when the measurement points move based on the determination; and a display unit configured to display a display image, characterized by further comprising an attitude estimation unit configured to estimate a movement period attitude which is an attitude of each of the measurement points during the movement period, based on the attitudes of each of the measurement points in the resting state before and after the movement period; a movement vector calculation unit configured to correct the acceleration of each of the measurement points on the basis of each of the respective movement period attitudes and to calculate respective movement vectors of each of the measurement points during the movement period, based on each of the corrected accelerations; and an image generation unit configured to generate a display image expressing each of the relative positions and each of the movement vectors. an insertion portion configured to be transformed; a plurality of attitude acquisition units which are disposed at a plurality of measurement points fixed to the insertion portion and each of which is configured to acquire acceleration applied to the respective measurement points and attitude information on attitudes of the respective measurement points in a resting state; a shape calculation unit configured to calculate the attitudes of each of the measurement points and relative positions of the measurement points to other of the measurement points, based on a position of each of the measurement points and each of the attitude information in the insertion portion; a movement determination unit configured to determine whether the measurement points move based on the acceleration; a movement period specification unit configured to specify a movement period when the measurement points move based on the determination; and a display unit configured to display a display image, characterized by further comprising an attitude estimation unit configured to estimate a movement period attitude which is an attitude of each of the measurement points during the movement period, based on the attitudes of each of the measurement points in the resting state before and after the movement period; a movement vector calculation unit configured to correct the acceleration of each of the measurement points on the basis of each of the respective movement period attitudes and to calculate respective movement vectors of each of the measurement points during the movement period, based on each of the corrected accelerations; and an image generation unit configured to generate a display image expressing each of the relative positions and each of the movement vectors.