The present invention is a solar cell provided with: a P-type silicon substrate having main surfaces, one of which is a light-receiving surface and the other of which is a back surface; and a plurality of back-surface electrodes each formed on a portion of the back surface, the P-type silicon substrate having an N-type layer in at least a portion of the light-receiving surface, the P-type silicon substrate having a contact region where the P-type silicon substrate is in contact with the back-surface electrodes, the solar cell being characterized in that the P-type silicon substrate is a gallium-doped silicon substrate, the resistivity of the P-type silicon substrate is 2.5 OMEGA.cm or less, and the back-surface electrode pitch Prm [mm] of the plurality of back-surface electrodes and the resistivity Rsub [OMEGA.cm] of the P-type silicon substrate satisfy a relationship represented by formula (1). As a result, provided are a solar cell employing a substrate which is inhibited from deteriorating due to light, wherein resistance loss is inhibited and conversion efficiency is excellent, and a solar cell module. log(Rsub) <= -log(Prm) + 1.0 (1)