To provide a device to prevent oil leak of a shaft bearing for a turbine rotor capable of easily and speedily adjusting aligning of a flinger in assemblage of a shaft bearing part of the turbine rotor.

A device 10 to prevent oil leak of a shaft bearing for a turbine rotor is provided with a shaft bearing base 1 having an engagement groove 1a and holding a turbine rotor shaft bearing 20, and a flinger having an engagement part 2a to be engaged with the engagement groove 1a of the shaft bearing base 1. On the other side of the shaft bearing 20 to the engagement part 2a of the flinger, an aligning block 12 is provided. On the shaft bearing base 1, an adjusting block part 11 to correspond to the aligning block 12 is provided. On either of the adjusting block part 11 and the aligning block 12, a vertical aligning bolt 14 abutting on the other is installed.