Abstract: Disclosed is a method for automatically controlling a focal point of a digital optical device, which: performs the steps of a focal point mode for performing a high-speed AF operation, and function processing high-capacity function image data; configures a function mode for detecting function focal point data and comparing it to a critical range; automatically performs switching between the focal point mode and the function mode by using an optical device; yields high-capacity function image data having an adjusted focal point in an environment in which the optical device is used where focal point distances change rapidly when a subject or the user of the optical device is moving; and performs required commands at high speed through the optical device when the user of the storing optical device inputs a required command once.