An electrostatic recording apparatus has a sensor for detecting a surface potential of a photosensitive member on which an electrostatic latent image is formed and a controller for controlling a developing bias voltage in accordance with the detected surface potential. The developing bias voltage includes an A.C. component and a D.C. component which are selectively used in accordance with a latent image potential. The frequency of the A.C. developing bias and the magnitude of the D.C. developing bias are variable so that an optimum quality of image is reproduced.