A road measurement method, wherein: photographing means photograph a road surface of a road and a roadside; scale formation means form, by a predetermined processing procedure, a scale image on a road image photographed by the photographing means, from a height of the photographing means from the road surface and an angle (α) that a photographing direction of the photographing means forms with a direction parallel to the road surface, wherein the scale image is a grid image with vertical lines extending parallel to a depth direction of the image from the respective section points and by horizontal lines intersecting the vertical lines so that rectangles of a predetermined size are arranged side by side on a horizontal plane of the road image, a measurement vehicle holds the photographing means and the scale formation means and travels on the road, the road being a photographing target, wherein when the measurement vehicle changes its traveling direction, the scale formation means rotates the scale image in accordance with a rotation angle (α) at which the photographing means rotates using the photographing direction as an axis, such that the scale image is parallel to the road surface in the road image; and a photographing time accepting unit accepts a distance travelled by the measurement vehicle from a rangefinder through an input interface and outputs an instruction signal every predetermined travelled distance, whereby the instruction signal is used to control the photographing time of the photographing means, so as to photograph a road surface and a roadside every predetermined traveled distance. photographing means photograph a road surface of a road and a roadside; scale formation means form, by a predetermined processing procedure, a scale image on a road image photographed by the photographing means, from a height of the photographing means from the road surface and an angle (α) that a photographing direction of the photographing means forms with a direction parallel to the road surface, wherein the scale image is a grid image with vertical lines extending parallel to a depth direction of the image from the respective section points and by horizontal lines intersecting the vertical lines so that rectangles of a predetermined size are arranged side by side on a horizontal plane of the road image, a measurement vehicle holds the photographing means and the scale formation means and travels on the road, the road being a photographing target, wherein when the measurement vehicle changes its traveling direction, the scale formation means rotates the scale image in accordance with a rotation angle (α) at which the photographing means rotates using the photographing direction as an axis, such that the scale image is parallel to the road surface in the road image; and a photographing time accepting unit accepts a distance travelled by the measurement vehicle from a rangefinder through an input interface and outputs an instruction signal every predetermined travelled distance, whereby the instruction signal is used to control the photographing time of the photographing means, so as to photograph a road surface and a roadside every predetermined traveled distance.