Butterfly valve

A butterfly valve for opening and closing an exhaust pipe communicating with an exhaust port of an engine, the butterfly valve comprising:

• a valve plate provided in the exhaust pipe;
• a valve shaft configured to cross the exhaust pipe and hold the valve plate;
• a bearing unit comprising an annular sealing bush and an annular support bush, which are separate components and into which the valve shaft is inserted, the bearing unit configured to slidably support the valve shaft;
• and
• a housing attached to the exhaust pipe and configured to accommodate the bearing unit arranged outside the exhaust pipe,
• wherein the support bush of the bearing unit is arranged between the housing and the sealing bush of the bearing unit and is in contact with the housing on an outer peripheral surface of the support bush, and
• wherein the sealing bush of the bearing unit is in contact with the housing on an outer peripheral surface of the sealing bush and is in contact with a flange of the valve shaft on a valve shaft opposing surface of the sealing bush.