Abstract: In order to measure specific heat, the measurement time is very long and the instrument is very expensive. The specific heat may be calculated based on the thermal time constant obtained from the change of the sample temperature when the predetermined amount of sample with known density at the first temperature is introduced in the environment at the second temperature. This measuring method can use the oscillatory densitometer. The predetermined amount corresponds to the volume of the sample to be introduced in the oscillatory densitometer, the density is a measurement result of the oscillatory densitometer, and the thermal time constant corresponds to the time constant of the oscillation period of the oscillatory densitometer.