A probe head in a nuclear magnetic resonance measurement apparatus includes a rotating mechanism. In the probe head, an exhaust gas having a high temperature or a low temperature is discharged from a discharge port of the rotating mechanism. An additive gas having room temperature is introduced into the probe head through a plurality of ejection holes. The additive gas is mixed with the exhaust gas, and, as a result, an exhaust gas mixture having a temperature closer to room temperature than is the temperature of the sample is produced. A deflector regulates the direction in which the exhaust gas flows.