An endoscope apparatus, an endoscope apparatus operation device, a method for controlling an endoscope apparatus, and the like are disclosed that simplify a process that switches a focus control process between an autofocus control process and a manual focus control process. The endoscope apparatus includes a focus control section (130) that performs a focus control process that controls an in-focus object plane position by controlling an optical system, a switch control section (120) that switches the focus control process between an autofocus control process and a manual focus control process, and an operation section (102) that is operated by a user, when the operation section (102) has been operated by the user during a period in which the focus control section (130) performs the autofocus control process, the switch control section (120) switching the focus control process from the autofocus control process to the manual focus control process, and the focus control section (130) moving the in-focus object plane position to a position that differs from the in-focus object plane position when the operation section (102) has been operated.
