Pure rotational transitions have been measured for the normal isotopologue of thioformaldehyde, H212C32S , in the ground vibrational state in the 110-370 GHz, 570-670 GHz, and 850-930 GHz frequency ranges. A global data set has been constructed consisting of prior microwave and millimeter-wave transitions, the submillimeter-wave and terahertz (THz) transitions reported here, and far-infrared data and ground state combination differences. The 783 different transition frequencies in the data set were fit to Watson's S-reduced Hamiltonian with 20 parameters, resulting in a dimensionless weighted root-mean-square deviation of 0.78. New frequency predictions have been made for astronomical observations based on the molecular parameters obtained in the present study.