To shorten the time required for automatic focusing and to stabilize the retrieval time.

The automatic focusing device is provided with an axis controller, an ITV camera 4, and an image processor which has FIFO memories 22a and 22b which receive the image data and a processor 19 and uses a constitution in which the axis controller changes position of the ITV camera 4 in Z-axis direction. The axis controller changes the relative distance between an object and the ITV camera 4 in the Z-axis direction. The axis controller detects a pre-determined measurement start point and transmits a measurement position arrival signal to an image processor. The image processor, after receiving the measurement position arrival signal, takes in the image data from the ITV camera 4 into the FIFO memories 22a and 22b. Focusing degree for each taking in is calculated by a processor 19. A peak point of the focusing degree is retrieved and the position of the peak point is sent to the axis controller. The ITV camera 4 is controlled to move so as to agree with the position of the peak point.