PURPOSE: To obtain a fiber sheet where optical fibers are arranged regularly, by arranging optical fibers on a plane at regular intervals and contracting thermally a film, which is contracted thermally only in the lateral direction, after fixing this film to each of both faces of the fiber group in the longitudinal direction.

CONSTITUTION: Optical fibers 1 are set to bobbins 2 and are pulled with a constant tension by fiber feed rollers 3 and are arranged at equal intervals by groove guides 4. Films 5 (adhesive is applied to one sides) which are contracted thermally only in the lateral (vertical) direction are fixed to both faces of the group of optical fibers 1 in the longitudinal direction of optical fibers 1 by a pair of nip rollers 8. They are sent into a heat chamber 10 by the first delivery roller 9 and are contracted thermally to obtain an optical fiber sheet-shaped material which is contracted only in the lateral direction. The regular arrangement due to this thermal contraction is used to apply this method to an optical sensor or the transportation of images.