A spunbonded elastic nonwoven fabric according to the invention comprises fibers formed from a polymer comprising a thermoplastic polyurethane elastomer, wherein the thermoplastic polyurethane elastomer has a starting temperature for solidifying of 65° C. or above as measured by a differential scanning calorimeter (DSC) and contains 3.00×106 or less polar-solvent-insoluble particles per g as counted on a particle size distribution analyzer, which is based on an electrical sensing zone method, equipped with an aperture tube having an orifice of 100 μm in diameter, and wherein the fibers have diameters such that the standard deviation of fiber diameters (Sn) divided by the average fiber diameter (Xave) (Sn/Xave) gives a value of 0.15 or less.