A valve mechanism , comprising: a valve having a valve roller ; a camshaft provided with a cam ; an intermediate swing arm located between the cam and the valve , the cam driving the valve to move by means of the intermediate swing arm swinging around an intermediate swing arm shaft , characterized in that the valve mechanism comprises: a fixed support comprising a fixed portion and a connecting portion , the connecting portion being connected with the fixed portion , and provided with a connecting-portion via hole running from top to bottom, and the connection portion defining an oil passage therein, the intermediate swing arm being mounted in the fixed portion , and the oil passage being connected with the connecting-portion via hole and configured to output lubricating oil to the intermediate swing arm shaft ; and a supporting base comprising a base body and a base-body camshaft supporting portion configured to support the camshaft ; wherein the supporting base defines a first supporting-base oil feeding passage and a second supporting-base oil feeding passage therein, the first supporting-base oil feeding passage is communicated with the connecting-portion via hole , and an upper end of the second supporting-base oil feeding passage extends to the base-body camshaft supporting portion , so as to output the lubricating oil to the camshaft . a valve having a valve roller ; a camshaft provided with a cam ; an intermediate swing arm located between the cam and the valve , the cam driving the valve to move by means of the intermediate swing arm swinging around an intermediate swing arm shaft , characterized in that the valve mechanism comprises: a fixed support comprising a fixed portion and a connecting portion , the connecting portion being connected with the fixed portion , and provided with a connecting-portion via hole running from top to bottom, and the connection portion defining an oil passage therein, the intermediate swing arm being mounted in the fixed portion , and the oil passage being connected with the connecting-portion via hole and configured to output lubricating oil to the intermediate swing arm shaft ; and a supporting base comprising a base body and a base-body camshaft supporting portion configured to support the camshaft ; wherein the supporting base defines a first supporting-base oil feeding passage and a second supporting-base oil feeding passage therein, the first supporting-base oil feeding passage is communicated with the connecting-portion via hole , and an upper end of the second supporting-base oil feeding passage extends to the base-body camshaft supporting portion , so as to output the lubricating oil to the camshaft . a fixed support comprising a fixed portion and a connecting portion , the connecting portion being connected with the fixed portion , and provided with a connecting-portion via hole running from top to bottom, and the connection portion defining an oil passage therein, the intermediate swing arm being mounted in the fixed portion , and the oil passage being connected with the connecting-portion via hole and configured to output lubricating oil to the intermediate swing arm shaft ; and a supporting base comprising a base body and a base-body camshaft supporting portion configured to support the camshaft ; wherein the supporting base defines a first supporting-base oil feeding passage and a second supporting-base oil feeding passage therein, the first supporting-base oil feeding passage is communicated with the connecting-portion via hole , and an upper end of the second supporting-base oil feeding passage extends to the base-body camshaft supporting portion , so as to output the lubricating oil to the camshaft . <EOS>