A double-row self-aligning roller bearing comprising: an inner ring; an outer ring having a raceway surface formed in a spherical shape; rollers (13a, 13b) interposed between the inner ring and the outer ring in two rows aligned in an axial direction, each of the rollers (13a, 13b) having an outer circumference formed in a spherical shape along the raceway surface of the outer ring; and a hard film comprising: a foundation layer formed directly on a surface of at least one bearing component selected from among the inner ring, the outer ring, and the rollers (13a, 13b); a mixed layer formed on the foundation layer and mainly formed of tungsten carbide and diamond-like carbon; and a surface layer formed on the mixed layer and mainly formed of diamond-like carbon, wherein: the double-row self-aligning roller bearing is configured to be used such that the hard film is brought into sliding contact or into rolling and sliding contact with other bearing component in a boundary lubrication state; and the mixed layer is formed such that a content rate of the tungsten carbide in the mixed layer is continuously or stepwise decreased and a content rate of the diamond-like carbon is continuously or stepwise increased from a side of the foundation layer toward a side of the surface layer; characterised in that the inner ring, the outer ring, and the rollers (13a, 13b) are formed of iron-based material; and the content of the hydrogen in the mixed layer is less than 10 atom%. an inner ring; an outer ring having a raceway surface formed in a spherical shape; rollers (13a, 13b) interposed between the inner ring and the outer ring in two rows aligned in an axial direction, each of the rollers (13a, 13b) having an outer circumference formed in a spherical shape along the raceway surface of the outer ring; and a hard film comprising: a foundation layer formed directly on a surface of at least one bearing component selected from among the inner ring, the outer ring, and the rollers (13a, 13b); a mixed layer formed on the foundation layer and mainly formed of tungsten carbide and diamond-like carbon; and a surface layer formed on the mixed layer and mainly formed of diamond-like carbon, wherein: the double-row self-aligning roller bearing is configured to be used such that the hard film is brought into sliding contact or into rolling and sliding contact with other bearing component in a boundary lubrication state; and the mixed layer is formed such that a content rate of the tungsten carbide in the mixed layer is continuously or stepwise decreased and a content rate of the diamond-like carbon is continuously or stepwise increased from a side of the foundation layer toward a side of the surface layer; characterised in that the inner ring, the outer ring, and the rollers (13a, 13b) are formed of iron-based material; and the content of the hydrogen in the mixed layer is less than 10 atom%. the double-row self-aligning roller bearing is configured to be used such that the hard film is brought into sliding contact or into rolling and sliding contact with other bearing component in a boundary lubrication state; and the mixed layer is formed such that a content rate of the tungsten carbide in the mixed layer is continuously or stepwise decreased and a content rate of the diamond-like carbon is continuously or stepwise increased from a side of the foundation layer toward a side of the surface layer; characterised in that the inner ring, the outer ring, and the rollers (13a, 13b) are formed of iron-based material; and the content of the hydrogen in the mixed layer is less than 10 atom%.