To develop and provide a fixture and a method for attaching a connection rod member, which enable anyone to easily and efficiently attach the connection rod member and which are excellent in safety, workability, and economic efficiency.

A rotation transmission part provided on a leading end side and a connection part provided on a back end side are each provided by being integrally formed. The rotation transmission part is provided by embedding a flexible member such as a urethane rubber provided with each of conical holes having large and small inside diameter dimensions and a depth dimension, suitable for the size of a male-side connection rod member using a central part. The connection part is provided with a connection hole with a pin for prevention of coming-off, which is suitable for a leading end connection part of rotation transmission means such as an impact wrench.