This invention relates to an improvement in a doctor blade device adapted for use in an automatic processor for printing plates, comprising at least one doctor blade made of a flexible material and being detachably mounted in a guide bar, and holding means for attaching the doctor blade to two side plates of the printing plate processor, the improvement comprising means connecting the guide bar with a carrier bar each end of which is adapted to be inserted from above into a channel section having an upwardly pointing opening and having two arms spaced by a web; means securing each channel section by its web to a side plate in such a manner that its two arms extend transversely to the transport direction of a printing plate in the direction of the interior of the printing plate processor; and support means at both ends of the upper surface of the carrier bar whereby the carrier bar together with the connected guide bar and the doctor blade rest upon said channel sections.