PROBLEM TO BE SOLVED: To provide an image forming apparatus of a proximity electrification system which obtains high image quality by improving accuracy and reliability of control of the gap of a non-contact electrification roller with respect to a photoreceptor and by preventing ununiform electrification caused by abnormal discharge, electrification failure, etc. SOLUTION: The image forming apparatus adjusts a gap between the non-contact electrification roller 1a and the photoreceptor 2 by disposing a gap hold member 8 between the electrification roller 1a and the photoreceptor 2 such that the member 8 is brought into firm contact with the roller 1a and the photoreceptor 2. In the image forming apparatus, the firm contact position of the gap hold member 8 is situated in the inside of firmly-pressed-in areas of flanges the parts of which are firmly pressed in the ends of the main body of the photoreceptor. COPYRIGHT: (C)2004,JPO&NCIPI