The manufacturing method of a solar cell includes forming a photoelectric conversion unit and forming an electrode connected to the photoelectric conversion unit. The step of forming the electrode includes forming a seed formation layer connected to the photoelectric conversion unit, forming an anti-oxidation layer on the seed formation layer, performing a thermal process such that a material of the seed formation layer and a material of the photoelectric conversion unit react with each other to form a chemical bonding layer at a portion at which the seed formation layer and the photoelectric conversion unit are adjacent to each other, forming a conductive layer and a capping layer on the seed formation layer in a state in which a mask is used on the seed formation layer, and patterning the seed formation layer using either the conductive layer or the capping layer as a mask.