The object of the present invention is to provide a hydrodynamic bearing, a method for manufacturing the same, and a spindle motor, with which the gap in the axial direction required for the smooth operation of a bearing can be sufficiently ensured. A method for manufacturing a hydrodynamic bearing comprising a shaft, a sleeve attached so as to be capable of relative rotation with respect to the shaft, a first flange unit 6 fixed to or integrated with the shaft, and a second flange unit fixed to the shaft, the method comprising at least inserting the shaft into the sleeve, and inserting the shaft into the second flange unit, pressing the top face of the second flange unit in the axial direction, and fixing the second flange unit to the shaft by welding the shaft and the second flange unit while maintaining the pressing state.