A focus control device comprising: a focus driving control unit adapted to generate a focus driving control signal for driving a focus lens of an imaging unit, to output the focus driving control signal to the imaging unit, to set a ranging area within an imaging screen for detecting a defocus amount in the set ranging area, and to detect the defocus amount in the set ranging area, characterized in that the focus driving control unit is further adapted to set a size of the ranging area to a predetermined speed priority ranging size and to perform a focus driving control wherein speed is prioritized by generating a focus driving control signal for driving the focus lens to a focusing position on basis of the defocus amount detected in the ranging area having the predetermined speed priority ranging size and a predetermined driving pattern indicating a movement speed of the focus lens, in case that the detected defocus amount is greater than a ranging area determination threshold set in advance, and to set the ranging area to a subject priority ranging size which is different from the predetermined speed priority ranging size and to perform a focus driving control wherein trackability, stability or precision is prioritized by generating a focus driving control signal on basis of the defocus amount detected in the ranging area having the subject priority ranging size and so that a state wherein a desired subject is in focus is maintained with high precision, in case that the detected defocus amount is equal to or less than the ranging area determination threshold. a focus driving control unit adapted to generate a focus driving control signal for driving a focus lens of an imaging unit, to output the focus driving control signal to the imaging unit, to set a ranging area within an imaging screen for detecting a defocus amount in the set ranging area, and to detect the defocus amount in the set ranging area, characterized in that the focus driving control unit is further adapted to set a size of the ranging area to a predetermined speed priority ranging size and to perform a focus driving control wherein speed is prioritized by generating a focus driving control signal for driving the focus lens to a focusing position on basis of the defocus amount detected in the ranging area having the predetermined speed priority ranging size and a predetermined driving pattern indicating a movement speed of the focus lens, in case that the detected defocus amount is greater than a ranging area determination threshold set in advance, and to set the ranging area to a subject priority ranging size which is different from the predetermined speed priority ranging size and to perform a focus driving control wherein trackability, stability or precision is prioritized by generating a focus driving control signal on basis of the defocus amount detected in the ranging area having the subject priority ranging size and so that a state wherein a desired subject is in focus is maintained with high precision, in case that the detected defocus amount is equal to or less than the ranging area determination threshold. to set a size of the ranging area to a predetermined speed priority ranging size and to perform a focus driving control wherein speed is prioritized by generating a focus driving control signal for driving the focus lens to a focusing position on basis of the defocus amount detected in the ranging area having the predetermined speed priority ranging size and a predetermined driving pattern indicating a movement speed of the focus lens, in case that the detected defocus amount is greater than a ranging area determination threshold set in advance, and to set the ranging area to a subject priority ranging size which is different from the predetermined speed priority ranging size and to perform a focus driving control wherein trackability, stability or precision is prioritized by generating a focus driving control signal on basis of the defocus amount detected in the ranging area having the subject priority ranging size and so that a state wherein a desired subject is in focus is maintained with high precision, in case that the detected defocus amount is equal to or less than the ranging area determination threshold.