1. An image measurement device which has a first measurement region acquisition unit for acquiring a first measurement region from an image and a second measurement region acquisition unit for acquiring a second measurement region, which is different from the first measurement region, from the image, and computes a distance between the first measurement region and the second measurement region from distance information corresponding to the first measurement region and distance information corresponding to the second measurement region, the image measurement device comprising: a distance computation unit that, after the first measurement region positioned on an object is displaced so as to be a region on the same object in response to an operation from an input unit that causes the first measuring region to be displaced on the image and the second measurement region positioned on an object is displaced in a region on the same object in accordance with an operation of a linear region following unit of a plane region deciding unit that causes a contour or a plane on the image, at which the second measurement region is positioned to be displaced, computes a distance between the first measurement region after the displacement and the second measurement region after the displacement, which is displaced by the linear region following unit or the plane region deciding unit.