PURPOSE: To give an excellent offset preventing capacity by forming a comparatively thin high resistance layer on the surface layer of a pressure roller, and charging electrostatically the resistance layer to the same polarity as that of a toner by contact triboelectrification to a recording material.

CONSTITUTION: As for a pressure roller 2, a low resistance elastic body layer 22 is provided comparatively thickly on the outside circumferential surface of a metallic roller core 21, and a high resistance elastic body layer 23 is provided comparatively thinly on its outside circumference. Also, the roller 2 is charged electrostatically to the same polarity as that of a toner charged electrostatically to negative, by a contact friction to a copy paper or a fixing roller 1. Such a characteristic is given by silicon rubber, etc. In case this pair of fixing rollers are used, the copy paper is charged electrostatically, for instance, to +410V, the pressure roller 2 is charged electrostatically to -700V, and an electrostatic attracting force of the copy paper P and the toner is increased. Therefore, an extremely excellent offset preventing capacity can be given.