We investigated the optical properties of stacking faults (SFs) in cubic silicon carbide by photoluminescence (PL) spectroscopy and mapping. The room-temperature PL spectra consisted of a 2.3 eV peak due to nitrogen and two undefined broad peaks at 1.7 eV and 0.95 eV. On the PL intensity mapping for the 2.3 eV peak, SFs appeared as dark lines. SFs which expose carbon atoms (SFC) and silicon atoms (SFSi) on the surface appeared as bright lines and dark lines, respectively, in PL mapping for the 1.7 eV and 0.95 eV peaks. We believe the two undefined peaks are associated with SFC. This technique allows us to detect SFs nondestructively and to distinguish between SFC and SFSi. We further suggest the presence of inhomogeneous stress around SFCs based on the broadening of the 2.3 eV peak.