The infrared spectra of 25 kinds of benzenesulfinamide and p-toluenesulfinamide derivatives were measured. The S-N bands were observed between 928 cm^-1 and 872 cm^-1 as in benzenesulfonamide and methanesulfonamide derivatives. Moreover, the bands near 1090 cm^-1 were found in all of the sulfinamide derivatives. The spectral change on deuteration were examined. In the compounds having -S-NH-and-S-NH₂ form, the bands near 900 cm^-1 region shifted to the lower wave number (about 110∼18 cm^-1). But no such shift has been observed in the bands near 1090 cm^-1 and in the range 1075∼1035 cm^-1.