PURPOSE: To prevent a fixing oil from being supplied too much to the roller in a fixing unit by interposing an oil amt. control sheet having a square hole of the size corresponding to the transverse size of the size of printing paper printed just before between the one roller and an oil supplying mechanism.

CONSTITUTION: A fixing section 2 has the fixing roller 6, the pressure contact roller 7 pressed to the fixing roller 6 and the oil supplying mechanism 8 which supplies the fixing oil for the printing paper on the outside surface of at least the one roller of these rollers, for example, the pressure contact roller 7. Further, the oil amt. control sheet 10 having the square hole of the size corresponding to the transverse size of the size of the printing paper printed just before is interposed between the pressure contact roller 7 which is the one roller and the oil supplying mechanism 8. The parts exclusive of the passed paper are prevented from being abundantly wet with much oil than need in this way.