To provide a propeller shaft assembly including a shaft structure and an insert member.

The insert member 250 is furnished with a front extremity 254 having a first groove hole 252 and a tail 258 having a second groove hole 256. The first groove hole 252 is arranged overlapping at least partially with the second groove hole 256 so that a zigzag arranged groove hole structure is generate, which guarantees the proper fitting when installed in the shaft structure 200.