There is provided a fixing belt that has sufficient fixing performance even at high sheet-feeding speeds of 100 ppm or more, does not cause offset even with respect to color toners, produces glossy high-quality images at the level of photograph image quality, and has high durability such that mechanical strength or image quality can hardly be reduced during continuous operation. The color image fixing belt of the invention is characterized by being made of a polyimide resin and has an inner diameter of no less than 300 mm, and the outer circumference surface of the belt has a surface roughness (Rz) of 1 .mu.m or less.