PURPOSE: To provide a power takeoff adapter mounted on a standard drive shaft of a power unit so as to permit the use of the unit for various applications without requiring the design of a plurality of separate drive shafts.

CONSTITUTION: A power takeoff adapter for a drive shaft provided in such a way as to be freely rotationally supported within a housing and to rotate about a drive axis 14 while having an end extended outward from the housing comprises a female receptacle 36 which has one end adapted to extend the drive shaft and secured to and supported by the drive shaft in such a way as to rotate about the drive axis, and which is located at the one end of the drive shaft including a cylindrical internal thread portion, and a male pin 34 including a cylindrical external thread portion complementary to the internal thread portion and secured to and drawn into the receptacle by being inserted into the receptacle and clamping a screw, while being located at one end of the power takeoff adapter and capable of being received by the receptacle.