An endoscope apparatus including an imaging section that includes a phase difference detection element for implementing phase detection autofocus, and acquires a captured image; a phase difference calculation section that calculates a phase difference based on a signal output from the phase difference detection element; a lens position selection section that selects a lens position that is either a near point-side lens position or a far point-side lens position based on the phase difference, the near point-side lens position and the far point-side lens position being discrete lens positions set in advance; a driver section that changes a lens position of the imaging section to the lens position selected by the lens position selection section; and a control section that controls an intensity of illumination light that is applied to an object. The lens position selection section determines whether or not the intensity is smaller than a given threshold value when the phase difference calculation section cannot detect the phase difference, selects the near point-side lens position when the lens position selection section has determined that the intensity is smaller than the threshold value, and selects the far point-side lens position when the lens position selection section has determined that the intensity is larger than the threshold value.