An image forming method and apparatus that improves the S/N ratio of a low frequency component without causing losses to the data of a high frequency component. Low frequency image data representing the low frequency component of a sample is obtained by a CCD imaging means by use of a binning mode, and high frequency image data representing the high frequency component of a sample is obtained by the CCD imaging means without the use of a binning process. The low frequency image data and the high frequency image data are combined to form a synthesized image representing the sample.