An automatic focusing device in which the intensity distributions of the images of an object which are formed by light beams passing through different portions of an optical system in a photographing device are detected as video signals. A correlation output is obtained from the video signals so that the focusing condition is detected from the peak position of the correlation output. When the peak position is not one for focalization, a drive direction signal is delivered to drive the optical system towards the focusing position. A low contrast detecting circuit is provided in which is counted how many times the correlation output becomes higher than a predetermined level in one focusing condition detecting operation, and when the count value reaches a predetermined value, the drive direction signal is made ineffected, so as to prevent the occurrence of a hunting phenomenon with the optical system.