A bifacial solar cell includes a substrate formed of a silicon wafer having an n-type conductivity; an emitter region positioned on a front surface of the substrate and having a p-type conductivity; a front negative fixed charge layer on the emitter region, and a front positive fixed charge layer on the front negative fixed charge; a plurality of first front electrodes extending in a first direction and connected to the emitter region through the front negative fixed charge layer and the front positive fixed charge layer; a plurality of second front electrodes extending in a second direction crossing the first direction and electrically and physically connected to the plurality of first front electrodes; a back aluminum oxide layer and a back silicon nitride layer on a back surface of the substrate; a plurality of back surface field regions extending in the first direction and locally positioned on the back surface of the substrate; a plurality of first back electrodes extending in the first direction and directly positioned on the plurality of back surface field regions through the back aluminum oxide layer and the back silicon nitride layer; and a plurality of second back electrodes extending in the second direction and electrically and physically connected to the plurality of first back electrodes, wherein the front negative fixed charge layer and the back aluminum oxide layer have the same thickness.