The present invention relates to an air conditioner with an ionizer which comprises: an ionizer to generate ions mounted in the vicinity of an air outlet, a carrier to move the ionizer, and a controller to control the ionizer and the carrier. The controller controls the carrier to move the ionizer to an initial point when power is supplied to the air conditioner or the power is changed from turn off to turn on. The controller can control a position of the ionizer with the carrier in response to a sensing signal of a sensor which senses a position of a person. Accordingly, a range of ion diffusion can be controlled efficiently, and by making the ions to be discharged to a specific direction the user presents thereto, effective improvement of an ion effect the user feel can be improved.