To provide a fixing jig capable of providing the constant proper fastening force regardless of users.

This fixing jig 22 is provided with a cylindrical main body 24 rotatably inserted into a rotary shaft, a locking lever 26 journaled on the cylindrical body 24 by a pin 36, and a spring 28 for rotating and energizing the locking lever 26. The locking lever 26 has a locking surface 26A having a center eccentric to a center of the pin 36, and the spring 28 energizes the locking lever 26 in the direction for increasing the engagement of the locking surface 26A with a surface of the rotary shaft. Whereby the fixing jig 22 can be inserted into the rotary shaft through its center hole 30 while pressing the lever 26, the locking surface 26A is engaged with the surface of the rotary shaft by releasing the lever 26, and the fixing jig 22 is fixed on the rotary shaft. The fixing jig 22 can be fixed and released by a simple and quick operation.