For a liquid applying mechanism of an ink jet printing apparatus, a liquid to be used for application to a medium is prevented from evaporating and leaking from a liquid holding member. An applying roller and the liquid holding member contact with each other to hold the liquid and apply the held liquid to a printing medium by way of the applying roller. In this configuration, the surface of the applying roller has no irregularities. Thereby, the applying roller can contact the liquid holding member to form an adequate liquid-tight seal therebetween.