A residual stress measuring method capable of measuring residual stress of the surface of an object to be inspected rapidly in a non-destructive non-contact manner, as well as a residual stress measuring system having such characteristics and being high in portability, are provided. The residual stress measuring system comprises a heating laser for heating an inspection area of an object to be inspected, a laser interferometer for irradiating the inspection area interferometric with laser light and measuring a deformation quantity within an elastic deformation range upon stress relief by heating in accordance with a laser interferometric method, and a data processor for measuring residual stress from the deformation quantity within the elastic deformation range upon stress relief of the object to be inspected.