To provide an imaging apparatus and a method of controlling the apparatus that enables improved automatic focus adjustment performance also in relation to an image having a shallow depth of field. An imaging element 103 includes a focus state detection unit for detecting a phase difference. A camera signal processing unit 106 generates a focus adjustment signal based on the imaging signal and outputs the signal to a camera control unit 109. The camera control unit 109 acquires an in-focus lens position in accordance with a focus lens based on a focus deviation amount based on a focus state detection result, calculates distance information related to the in-focus distance on the image screen, and controls the driving of the focus lens 102 based on the distance information and the focus adjustment signal from the camera signal processing unit 106. When a difference between the in-focus lens position and the position of the focus lens at the current time exceeds a threshold, the camera control unit 109 drives the focus lens to the in-focus lens position based on the distance information. When the difference between the in-focus lens position and the focus lens position at the current time is less than or equal to the threshold, the camera control unit 109 executes the in-focus control based on the focus adjustment signal.