A solar cell can include a substrate of a first conductive type; an emitter region which is positioned at a front surface of the substrate and has a second conductive type different from the first conductive type; a back surface field region which is positioned at a back surface opposite the front surface of the substrate; a front passivation region including a plurality of layers which are sequentially positioned on the emitter region; a back passivation region including a plurality of layers which are sequentially positioned on the back surface field region; a front electrode part which passes through the front passivation region and is connected to the emitter region, wherein the front electrode part comprises a plurality of front electrodes that are apart from each other and a front bus bar connecting the plurality of front electrodes; a back electrode part which passes through the back passivation region and is connected to the back surface field region, wherein the back electrode part comprises a plurality of back electrodes that are apart from each other and a back bus bar connecting the plurality of back electrodes, wherein the front passivation region includes a first aluminum oxide layer and the back passivation region includes a second aluminum oxide layer.