Ladder program edition device

A ladder program edition device that causes a plus bus bar and a minus bus bar in a ladder diagram to be displayed on a screen of a display unit, causes a plurality of auxiliary lines to be vertically and laterally displayed in a region between the plus bus bar and the minus bus bar, thereby partitioning the region into a plurality of cells, causes circuit elements that constitute a ladder diagram to be symbolically displayed in mutually separate cells, and edits a ladder diagram in which at least one input condition corresponds to one output condition, the ladder program edition device comprising:

• an input unit that inputs a command related to editing of the ladder diagram;
• and
• an edit control unit that arranges the circuit elements in cells on the screen of the display unit based on a command from the input unit, generates data of a logical expression corresponding to a logical structure in the ladder diagram by specifying an aggregate of the arranged circuit elements in each row as a circuit unit to be connected in parallel with each other, specifies circuit elements to be connected in parallel with each other in the ladder diagram based on the data of the logical expression, and connects output ends of the circuit elements by a connection line.