A method for naturally following a main shooting subject with a frame in successively displayed captured images, the method comprising: obtaining in each of the captured images a main shooting subject; creating a frame surrounding an identified region indicating the main shooting subject; and causing a display unit to display composite images on a screen, each composite image including the frame and an image of the captured images, such that the frame follows the main shooting subject, characterized by obtaining a first change of the main shooting subject in a Y-axis corresponding to an up-and-down motion of the main shooting subject and a second change of the main shooting subject in a X-axis from the central coordinates of an identified region of the main shooting subject in a current image and the central coordinates of the frame already displayed, determining whether the first change and the second change are equal to or exceed a first reference value and a second reference value respectively, and calculating a third change by multiplying the first change by a first constant, which is smaller than 1, and a fourth change by multiplying the second change by a second constant, which is smaller than 1 and larger than the first constant, wherein, when the first change is more than or equal to the first reference value, the coordinate of the Y-axis of the frame is updated based on the third change when displaying the current image, and when the second change is more than or equal to the second reference value, the coordinate of the X-axis of the frame is updated based on the fourth change when displaying the current image; and wherein the frame is not updated otherwise. obtaining in each of the captured images a main shooting subject; creating a frame surrounding an identified region indicating the main shooting subject; and causing a display unit to display composite images on a screen, each composite image including the frame and an image of the captured images, such that the frame follows the main shooting subject, characterized by obtaining a first change of the main shooting subject in a Y-axis corresponding to an up-and-down motion of the main shooting subject and a second change of the main shooting subject in a X-axis from the central coordinates of an identified region of the main shooting subject in a current image and the central coordinates of the frame already displayed, determining whether the first change and the second change are equal to or exceed a first reference value and a second reference value respectively, and calculating a third change by multiplying the first change by a first constant, which is smaller than 1, and a fourth change by multiplying the second change by a second constant, which is smaller than 1 and larger than the first constant, wherein, when the first change is more than or equal to the first reference value, the coordinate of the Y-axis of the frame is updated based on the third change when displaying the current image, and when the second change is more than or equal to the second reference value, the coordinate of the X-axis of the frame is updated based on the fourth change when displaying the current image; and wherein the frame is not updated otherwise.