PURPOSE: To ensure high accuracy of measurement at low cost by an arrangement wherein a line pattern is reflected using a mirror having specifically curved or inclining surface.

CONSTITUTION: When the surface of a person is measured three-dimensionally, a camera 1 is useful for picking up the image of the person standing on a balance plate 2. A flash projector 3 is used for projecting contour-lines extending horizontally and the projector 3 produces a line pattern using a slide. A mirror 4 is arranged in the optical path and the surface of mirror directing toward the projector 3 is curved such that respective rays 5a-5e impinging on the mirror are reflected at the same angle. The parallel projection eliminates the need of various exchanges at individual measuring points. The exchange rate is constant at respective measuring points. When a line pattern is reflected at 45°, no exchange is required and the deflection of line corresponds to inflation or depression at that position. Consequently, a measuring screen can be directed accurately onto a measuring plane 6 formed, as a vertical imaginary plane, within one third of the balance plate 2 on the front side.