PURPOSE: To reduce parts in number and to simplify in structure, by applying bearings of two press fixing rolls, by utilizing the retaining strength of curved parts of an endless beltlike elastic body in a shape fitting into those bearings when the elastic body is deformed elastically.

CONSTITUTION: The bearings 2 and 3 of the fixing rolls 4 and 5 are pressed by a spring 11 at pressure necessary for fixation. When no external force is applied, the shape of the spring 11 is as shown by a dotted line 12, but when appropriate external force is applied thereto as shown by arrows 17 and 18, the shape of the spring 11 is as shown by a solid line. Then, the bearings 2 and 3 wherein the fixing rolls 4 and 5 are pressed are pressed in the spring 11 in the solid-line shape as shown in a figure and then the spring 11 is released from the external force in the directions of the arrows 17 and 18 to complete the assembly, applying pressure to the bearings invariably. Thus, the parts are reduced in number and simplified in structure.