An object is to provide a printing machine nip checking system and the like that facilitates a nip checking operation. In the invention, a subject roller selecting section 10 is provided that selects a roller of which a nip width is to be checked. When a subject is narrowed, a main gear rotation angle calculating section 11 determines a rotation angle of the selected roller, in addition to a rotation direction. A main gear rotation driving section 13 connected to the main gear rotation angle calculating section 11 rotates a main gear 18 by the calculated desired angle, after the main gear 18 is stopped for a certain amount of time. As a result, an operator can visually recognize a nip on a subject gear without particularly considering the rotation direction and the rotation angle of the main gear 18.