Opening/closing mechanism of intake member

An opening/closing mechanism, comprising:

• an intake member which accommodates a filter part and has an opening leading to a carburetor in an end wall opposing the filter part;
• an opening/closing member which is disposed between the filter part and the end wall, and opens/closes the opening;
• and
• a working member which is disposed on an opposite side to the opening/closing member so as to interpose the end wall between the working member and the opening/closing member, and allows the opening/closing member to be operated,
• wherein the working member includes:
• an arm part which extends along the end wall and is linked with the opening/closing member to interpose the end wall at one end part, and a holding part provided to another end part of the arm part,
• wherein the intake member has a guide hole into which the arm part is inserted and which guides movement of the arm part, and
• wherein the holding part is disposed to project out of the guide hole, is provided to be wider than the arm part, extends from the arm part towards a side opposite to the carburetor, and has a notch part at a surface opposing a side wall of the intake member, wherein the notch part is obliquely notched out so as to gradually become a narrow shape extending toward a linking part with the arm part.