PROBLEM TO BE SOLVED: To provide a paste composition, which can fully achieve the BSF effect at least equal to or better than the conventional ones when used for both of the case where a thick rear-side electrode layer is formed on a thick silicon semiconductor substrate and the case where a thin rear-side electrode layer is formed on a thin silicon semiconductor substrate, and can achieve the BSF effect equal to or better than the conventional ones, while reducing deformation of the silicon semiconductor substrate after firing when used for the case where a thin rear-side electrode layer is formed on a thin silicon semiconductor substrate, and to provide a solar battery element having an electrode formed by the use of such a paste composition. SOLUTION: The paste composition contains aluminum powder as conductive powder, and a total content of iron and titanium contained as unavoidable impurity elements is 0.07% in mass or less. The solar battery element has a rear-side electrode 8 which is formed by applying the paste composition on the rear side of a silicon semiconductor substrate 1 followed by firing. COPYRIGHT: (C)2009,JPO&INPIT