A method of manufacturing a silicon carbide single crystal includes steps of preparing a crucible, a source material disposed toward a bottom surface in the crucible, a seed crystal disposed to face the source material toward a top surface in the crucible, a resistive heater, and a heat insulator configured to be able to accommodate the crucible therein, measuring a mass of at least a portion of the heat insulator, comparing a measured value of the mass obtained in the measuring step with a threshold value, and growing a silicon carbide single crystal on the seed crystal by sublimation of the source material by heating the crucible placed in the heat insulator with the resistive heater. When the measured value of the mass is lower than the threshold value in the comparing step, the step of growing a silicon carbide single crystal is performed at least one or more times.