A substrate for artificial leather comprising a nonwoven fabric of bundles of microfine filaments. The substrate for artificial leather simultaneously satisfies the following requirements 1 to 4: (1) the bundle of microfine filaments comprises 8 to 70 microfine filaments having a cross-sectional shape of nearly circle; (2) the bundle of microfine filaments has a cross-sectional area of 170 to 700 μm2 and a flatness of 4.0 or less; (3) on a cross section parallel to a thickness direction of the nonwoven fabric body, cross sections of the microfine fiber bundles exist in a density of 1500 to 3000/mm2; and (4) on a cross section parallel to a thickness direction of the nonwoven fabric body, gaps between the microfine fiber bundles have a size of 70 μm or less. By satisfying the requirements, the substrate for artificial leather combines high level of sensuous qualities and high level of physical properties which have been considered to be mutually exclusive.