An inkjet printing apparatus includes an ink tank that contains an ink to be supplied to a printing head that ejects the ink, the ink being injected from an ink bottle. The inkjet printing apparatus further includes an injection assistance member including a first passage and a second passage. The first passage is defined by a first upper end portion opening toward the outside of the ink tank and a first lower end portion opening toward the inside of the ink tank. The second passage is defined by a second upper end portion opening toward the outside of the ink tank and projecting upward less than the first upper end portion and a second lower end portion opening toward the inside of the ink tank and larger than the first lower end portion in terms of a distance from the bottom surface of the ink tank.