A printing apparatus comprising: a print head including a plurality of nozzles each arranged to eject a liquid droplet to a print medium; a control means configured to control drive of each of the nozzles so as to eject the liquid droplet; a sensor arranged to detect the liquid droplet ejected from each of the nozzles; a determination means configured to perform determination as to whether or not a swirl of the liquid droplet due to a variation or turbulence of a surrounding airflow is present in a case where a nozzle of the plurality of nozzles is driven by the control means; an adjustment means configured to perform adjustment of an ejection interval between nozzles in a case of detecting the liquid droplet by using the sensor, the adjustment being carried out based on the determination as to whether or not the swirl is present; and an assumed ejection failure determination means configured to determine one target nozzle out of the plurality of nozzles driven by the control means as the target nozzle having an assumed ejection failure in a case where the sensor fails to detect the liquid droplet from the target nozzle; characterized by a designation means configured to designate a nozzle group including the nozzle determined to have the assumed ejection failure by the assumed ejection failure determination means, wherein the determination means determines whether or not the swirl is present in the nozzle group by causing the control means to drive each of the nozzles in the nozzle group, and in a case (S708:YES) where the determination means determines that swirl is present in the nozzle group, the adjustment means performs the adjustment of the ejection interval between the nozzles in the nozzle group, and the control means performs control to subject each of the nozzles in the nozzle group to detection of the liquid droplet again by using the sensor. a print head including a plurality of nozzles each arranged to eject a liquid droplet to a print medium; a control means configured to control drive of each of the nozzles so as to eject the liquid droplet; a sensor arranged to detect the liquid droplet ejected from each of the nozzles; a determination means configured to perform determination as to whether or not a swirl of the liquid droplet due to a variation or turbulence of a surrounding airflow is present in a case where a nozzle of the plurality of nozzles is driven by the control means; an adjustment means configured to perform adjustment of an ejection interval between nozzles in a case of detecting the liquid droplet by using the sensor, the adjustment being carried out based on the determination as to whether or not the swirl is present; and an assumed ejection failure determination means configured to determine one target nozzle out of the plurality of nozzles driven by the control means as the target nozzle having an assumed ejection failure in a case where the sensor fails to detect the liquid droplet from the target nozzle; characterized by a designation means configured to designate a nozzle group including the nozzle determined to have the assumed ejection failure by the assumed ejection failure determination means, wherein the determination means determines whether or not the swirl is present in the nozzle group by causing the control means to drive each of the nozzles in the nozzle group, and in a case (S708:YES) where the determination means determines that swirl is present in the nozzle group, the adjustment means performs the adjustment of the ejection interval between the nozzles in the nozzle group, and the control means performs control to subject each of the nozzles in the nozzle group to detection of the liquid droplet again by using the sensor. the adjustment means performs the adjustment of the ejection interval between the nozzles in the nozzle group, and the control means performs control to subject each of the nozzles in the nozzle group to detection of the liquid droplet again by using the sensor.