PURPOSE: To smoothly slide an adapted part and prevent a valve from sticking, by forming a lubricating surface, constituted by applying a mixture containing a solid lubricant and a silicon system resin binder, on the internal peripheral surface of an intake way adapting a peripheral part of the throttle valve.

CONSTITUTION: A throttle body main unit 1 forms in its central part an intake way 2 facing a horizontal direction further provides a throttle valve 4 turnably by a throttle shaft 3 for operating the intake way 2 to be opened and closed. Here a lubricant 19 is applied to a portion of the intake way 2 adapted to a peripheral part of the valve 4 in order that the throttle valve 4 ensures its close attachability to an internal peripheral surface of the intake way 2 adapting the peripheral part of the valve 4 and it is simultaneously prevented from sticking. And the lubricant 19 is formed by mixing a solid lubricant of molybdenum disulfide or the like in silicon system resin binder. In this way, the throttle body main unit smoothly slides the throttle valve 4 with the intake way 2 while improves air-tightness of the valve 4.