An inkjet printing apparatus includes a surface acoustic wave module including an inner passage and a surface acoustic wave generator around the inner passage; and an outflow passage connected to the surface acoustic wave module to discharge ink, where the outflow passage includes a first outflow passage connected to the inner passage to discharge first ink particles and a second outflow passage connected to the inner passage to discharge second ink particles having an average diameter smaller than that of the first ink particles, and the surface acoustic wave generator is closer to the second outflow passage than the first outflow passage.