An image processing device (100; 450; 500; 850) comprising: an image acquisition unit (106; 256; 304) configured to acquire 360° images; and a rotational angle computation unit (112; 258; 504; 652; 706; 852) configured to compute a rotational angle of the 360° images in a manner that a reference point included in the 360° images is positioned in a designated orientation with respect to a center of the 360° images, wherein: the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to compute the rotational angle using a point of regard estimated in the 360° images as the reference point, the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to estimate the point of regard on a basis of an analysis result of the 360° images, the image acquisition unit (106; 256; 304) is configured to acquire the 360° images taken in chronological succession via a fisheye lens, and the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to estimate that a point of origin of motion vectors in the 360° images is the point of regard, and when the point of origin is detected in a peripheral portion of the 360° images, the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to estimate that the point of origin is the point of regard. an image acquisition unit (106; 256; 304) configured to acquire 360° images; and a rotational angle computation unit (112; 258; 504; 652; 706; 852) configured to compute a rotational angle of the 360° images in a manner that a reference point included in the 360° images is positioned in a designated orientation with respect to a center of the 360° images, wherein: the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to compute the rotational angle using a point of regard estimated in the 360° images as the reference point, the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to estimate the point of regard on a basis of an analysis result of the 360° images, the image acquisition unit (106; 256; 304) is configured to acquire the 360° images taken in chronological succession via a fisheye lens, and the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to estimate that a point of origin of motion vectors in the 360° images is the point of regard, and the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to compute the rotational angle using a point of regard estimated in the 360° images as the reference point, the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to estimate the point of regard on a basis of an analysis result of the 360° images, the image acquisition unit (106; 256; 304) is configured to acquire the 360° images taken in chronological succession via a fisheye lens, and the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to estimate that a point of origin of motion vectors in the 360° images is the point of regard, and when the point of origin is detected in a peripheral portion of the 360° images, the rotational angle computation unit (112; 258; 504; 652; 706; 852) is configured to estimate that the point of origin is the point of regard.