Opening/closing mechanism for opening/closing member

An opening/closing mechanism for an opening/closing member, comprising:

• a hinge device configured to rotate the opening/closing member relative to a vehicle body;
• and
• a latch device configured to be brought into engagement with a striker provided on the vehicle body to hold the opening/closing member in a closed state,
• wherein the hinge device comprises:
• an electric driving device provided on the opening/closing member and configured to rotate the opening/closing member by means of a driving force of a motor;
• and
• a coupling configured to couple a body-side engagement portion provided on the vehicle body and an output shaft of the electric driving device together, and
• wherein the coupling comprises:
• a first cylindrical portion provided at a first end side of the coupling and having a fitting hole portion, to which the output shaft of the electric driving device is spline fit;
• a second cylindrical portion provided at a second end side of the coupling, which is opposite to the first end side, and having a fitting recessed portion configured to fit on the body-side engagement portion;
• and
• a coupling portion where the first cylindrical portion and the second cylindrical portion are coupled together.