A method for manufacturing a solar cell, the method comprising: forming a passivation layer on a rear surface of a substrate of a first conductivity type; forming an emitter region of a second conductivity type on a front surface of the substrate, the second conductivity type being opposite to the first conductivity type; applying a rear electrode paste to form rear electrodes on the passivation layer; locally thermally treating portions of the rear electrode paste to make electrical contact through the passivation layer by irradiating a laser beam; drying the rear electrode paste at a temperature of 120°C to 200°C after the local thermal treatment process; applying a front electrode paste over the emitter region after drying the rear electrode paste; forming a front electrode region to be electrically connected to the emitter region by thermally treating the front electrode paste; and forming the rear electrodes by thermally treating the entire rear electrode paste at a temperature of 750°C to 800°C, wherein in the local thermal treatment process, by the irradiation of the laser beam, a plurality of via holes are formed in the passivation layer, a plurality of grooves are formed in the rear surface of the substrate, and portions of the rear electrode paste are spaced apart, wherein during the drying process, the rear electrode paste flows into the plurality of grooves through the via holes of the passivation layer and is electrically connected to the substrate and the spaced-apart portions of the rear electrode paste are reconnected by the rear electrode paste filling the grooves of the substrate, wherein the forming of the rear electrodes by thermally treating the entire rear electrode paste and the forming of the front electrode region are carried out simultaneously by the same thermal treatment process, and wherein a plurality of back surface field regions is formed between the rear electrodes and the substrate in the forming process of the rear electrodes by the conductive material contained in the rear electrodes being diffused toward the substrate from connecting portions of the rear electrodes which penetrate into the substrate through the via holes of the passivation layer and are connected to the substrate. forming a passivation layer on a rear surface of a substrate of a first conductivity type; forming an emitter region of a second conductivity type on a front surface of the substrate, the second conductivity type being opposite to the first conductivity type; applying a rear electrode paste to form rear electrodes on the passivation layer; locally thermally treating portions of the rear electrode paste to make electrical contact through the passivation layer by irradiating a laser beam; drying the rear electrode paste at a temperature of 120°C to 200°C after the local thermal treatment process; applying a front electrode paste over the emitter region after drying the rear electrode paste; forming a front electrode region to be electrically connected to the emitter region by thermally treating the front electrode paste; and forming the rear electrodes by thermally treating the entire rear electrode paste at a temperature of 750°C to 800°C, wherein in the local thermal treatment process, by the irradiation of the laser beam, a plurality of via holes are formed in the passivation layer, a plurality of grooves are formed in the rear surface of the substrate, and portions of the rear electrode paste are spaced apart, wherein during the drying process, the rear electrode paste flows into the plurality of grooves through the via holes of the passivation layer and is electrically connected to the substrate and the spaced-apart portions of the rear electrode paste are reconnected by the rear electrode paste filling the grooves of the substrate, wherein the forming of the rear electrodes by thermally treating the entire rear electrode paste and the forming of the front electrode region are carried out simultaneously by the same thermal treatment process, and wherein a plurality of back surface field regions is formed between the rear electrodes and the substrate in the forming process of the rear electrodes by the conductive material contained in the rear electrodes being diffused toward the substrate from connecting portions of the rear electrodes which penetrate into the substrate through the via holes of the passivation layer and are connected to the substrate.