PURPOSE: To obtain a device having large tolerance through simple constitution, to provide it with high resolution and propagation efficiency, and to propagate a picture of less chromatic aberration, by using lenses and prisms in combination for a lens system picture processor applicable to facsimile, etc.

CONSTITUTION: The light signal of a picture 20 to be propagated which is incident to the 1st convex lenses 21a and 21b is collimated by the 1st prisms 22a and 22b into parallel light beams l1 and l2, which are made incident to the 2nd convex lenses 23a and 23b. Further, they are guided to the 2nd prisms 2a and 2b through the 2nd convex lenses 23a and 23b and the 3rd convex lenses 24a and 24b, and entered into a photodetection body 27 by the 2nd prisms 25a and 25b and the 3rd convex lenses 26a and 26b, wherein they are converted into electric signals. Therefore, when this constitution is applied to the character read part of a facsimile equipment, tolerance to a shift of a character surface is obtained, characters are read with sufficiently high resolution, and chromatic aberration is less, so that application to color processing is suitable.