An apparatus includes: a similar plant information retrieval unit retrieving plant information of a similar plant similar to a creation object plant from plant information versus control logic diagram association information stored in a plant information versus control logic diagram association information storage unit; a plant information difference detector comparing the plant information of the creation object plant with the plant information of the similar plant to acquire difference information; a plant information editor that, based on the difference information, deletes an element included in the similar plant but unnecessary for the creation object plant, and retrieves an element included in the creation object plant but not included in the similar plant from the plant information versus control logic diagram association information storage unit to add the retrieved element; and a plant information editing result display displaying a result of the plant information editor.