Abstract: A heat-resistant nickel-based alloy having excellent welding properties, said nickel-based alloy consisting essentially of, in terms of wt. %, 0.05 to 0.25% of C, 18 to 25% of Cr, 15 to 25% of Co, at least one selected from the group consisting of up to 3.5% of Mo and 5 to 10% of W, with W+1/2Mo being 5 to 10%, 1.0 to 5.0% of Ti, 1.0 to 4.0% of Al, 0.5 to 4.5% of Ta, 0.2 to 3.0% of Nb, 0.005 to 0.10% of Zr, 0.001 to 0.01% of B and the balance being Ni and unavoidable impurities, wherein the (Al+Ti) content and the (W+1/2Mo) content are within the range surrounded by the lines connecting points A (Al+Ti: 5%, W+1/2Mo: 10%), B (Al+Ti: 5%, W+1/2Mo: 5%), C (Al+Ti: 7%, W+1/2Mo: 5%), and D (Al+Ti: 7%, W+1/2Mo: 10%) excluding the line A-B in FIG. 1.