PURPOSE: To make blur inconspicuous and to improve lighting efficiency by disposing a cylindrical lens between a thin and long light source and data to be imprinted in a data imprinting device which employs the negative system of a camera.

CONSTITUTION: The cylindrical lens 18 is disposed between a lamp 8 and data 12 to be imprinted so that the cylinder axis is at right angles to the paper surface, i.e. parallel to the lengthwise direction of a filament 8a, and it has positive power in the direction parallel to the paper surface. The distance from the incandescent lamp 8 is so preset that the amount of blur in the lengtwise direction of the filament when the lens 18 is not used is within a permissible lens and blur is inconspicuous. When the cylinder axis direction of the lens 18 is an (x) direction and the direction perpendicular to it is an (y) direction, the mounts of flur in the (x) and (y) directions become nearly equal to each other, but they are almost equal to the x-directional amount of blur when the lens set within the permissible range is not used and inconspicuous. Further, the illuminance on a film surface is set 2.5W4 times as great as when the lens 18 is not used.