To provide a hydrodynamic bearing excellent in shock-durability and sliding performance.

A motor attached in a hard disk drive comprises a hydrodynamic bearing 4 which has a shaft 41 and sleeve 42 in which the shaft 41 is inserted. The sliding performance of the hydrodynamic bearing 4 with excellent shock-durability can be improved in such a way that the sleeve 42 is formed by phosphor bronze, and that a plating layer 420 formed by electroless nickel plating is arranged on a surface of the sleeve 42 after processing surface treatment by wood bath.