With use of a fine copper-based powder, specifically a copper-based powder that contains particles each having a diameter of 45 μm or less by 80 weight % or more, an air permeability can be significantly reduced. When this copper-based powder is used, a sintered metal can be easily formed to contain copper by 40% or less (contain iron by 60% or more) to enhance abrasion resistance, and to have an oil permeability of 1.00 g/10 min or less to increase an oil film formation rate.