A bonding composition contains copper powder, a liquid medium, and a reducing agent. The reducing agent contains at least one amino group and a plurality of hydroxyl groups. The reducing agent has a boiling point that is higher than the boiling point of the liquid medium. The reducing agent has a melting point that is equal to or below the sintering temperature of the copper powder. Preferably, the reducing agent is bis(2hydroxyethyl)iminotris(hydroxymethyl)methane. Preferably, the bonding composition has a viscosity of from 10 Pa·s to 200 Pa·s at a shear rate of 10 s-1 at 25° C. Preferably, the bonding composition contains from 0.1 parts to 10 parts by mass of the reducing agent and from 10 parts to 40 parts by mass of the liquid medium with respect to 100 parts by mass of the copper powder.