A Ni-base superalloy having a chemical composition comprising Al: 4.5-7.0 wt %, Ta+Nb+Ti: 0.1-4.0 wt %, with Ta being less than 4.0 wt %, Mo: 1.0-8.0 wt %, W: 0.0-10.0 wt %, Re: 2.0-8.0 wt %, Hf: 0.0-1.0 wt %, Cr: 2.0-10.0 wt %, Co: 0.0-15.0 wt %, Ru: 0.0-5.0 wt %, and the balance being Ni and unavoidable impurities, and a method for producing the same are disclosed. The Ni-base superalloy has excellent creep property at high temperature and is suitable for use as a member at high temperature under high stress.