An inkjet printing apparatus includes a mechanism for opening and closing an ink supply route between an ink tank and a printing head and capable of attaching and removing the ink tank by a horizontal movement. More specifically, a moving member 60 and the communication pipe 51 engaged therewith are moved upward by moving an operation member 70 upward. As a result, the communication pipe 51 moves into an ink lead chamber 16 and a communication channel 52 of the communication pipe 51 comes into communication with the ink lead chamber 16 through its opening. In this way, the ink lead chamber 16, namely, an ink storage chamber 12 comes into communication with a liquid chamber 50 of a printing head 20. An ink supply route is opened in this manner. The ink supply route is closed by the reverse operation to that mentioned above.