A measurement device for a vehicle seat includes a memory; a processor coupled to the memory; a headrest body of a headrest; a first side section of the headrest that is swingable toward a seat front side so as to support the neck of the vehicle occupant; a second side section of the headrest that is swingable toward the seat front side so as to support the neck of the vehicle occupant; a first electrode provided at the first side section and contacting the neck in a state in which the first side section is supporting the neck; and a second electrode provided at the second side section and contacting the neck in a state in which the second side section is supporting the neck. The processor is configured to acquire a waveform of a potential difference based on the potential difference between the first electrode and the second electrode over time.