A ladder circuit editing device provided with an inputted region which receives and edits a sequence program of a program controller in the form of a ladder diagram and is stored with at least one circuit pattern that has been received, and an uninputted region where a new circuit pattern is to be inputted and which successively receives circuit patterns from the inputted region, the inputted region comprising a circuit pattern extracting means which compares constituent elements of a circuit pattern that is being inputted into the uninputted region with constituent elements of a circuit pattern stored in the inputted region and extracts circuit patterns including constituent elements that are in agreement, a means for displaying the extracted circuit patterns on an input screen, and a means for copying the extracted circuit patterns on the uninputted region according to the input of operation.
