Provided is a method of welding a shaft and a wheel in a turbine shaft. A target surface with a hole is provided to any one of the shaft and the wheel. An opposed surface is provided to the other one of the shaft and the wheel. The opposed surface includes an opposed portion opposed to the target surface, and a non-opposed portion formed continuously from the opposed portion toward a center side while facing onto the hole. The welding method includes: disposing the target surface and the opposed surface such that the they are opposed to each other while establishing a state of surface contact; and welding them by beam irradiation from outside in a radial direction of the shaft toward inside in the radial direction thereof based on a condition to cause a depth of fusion to reach a position on a center side beyond the opposed portion.