There are provided a copper-based sintered sliding material comprising a steel back metal layer, and a sintered layer made of Cu or a Cu-based alloy which is bonded onto the steel back metal layer, the steel back metal layer having a hardness not less than 160 Hv and an elongation not less than 10%, the sintered layer having a hardness not more than 130 Hv and crystal grains each provided with a grain size not more than 45 nullm, a method of producing the sliding material, and a sliding bearing formed of the sliding material.