A measurement device for measuring an airflow volume of a wind-blowing apparatus, comprising: a housing that is formed of a resin material, said housing constituting an air duct with an air inlet and an air outlet, the air inlet being configured to take in air, the air outlet being configured to send out the taken air; an opening member installed inside the air duct of the housing, the opening member including an opening allowing the air taken from the air inlet to pass therethrough; pressure sensors (5a, 5b) configured to measure air pressures before and after the air passes through the opening member in the air duct; a variable orifice provided on the opening member to enlarge or contract the size of the diameter of the opening of the opening member; a display; a control unit coupled to the pressure sensors (5a, 5b); and a straightening grid located in the air duct of the housing and configured to straighten the air taken from the air inlet of the housing; wherein: the pressure sensors (5a, 5b) are configured to measure a first static pressure, a second static pressure, and a third static pressure, the first static pressure being air pressure from the air inlet of the housing to the straightening grid in the air duct of the housing, the second static pressure being air pressure from the straightening grid to the opening member, the third static pressure being air pressure after the air has passed through the opening member, and the control unit is configured: to calculate the airflow volume and a static pressure of the wind-blowing apparatus using measurement values of the air pressures before and after the air passes through the opening member; to calculate the airflow volume on the basis of a differential pressure between the second static pressure and the third static pressure; to display the calculated airflow volume and static pressure on the display; and to calculate a ventilation resistance of the wind-blowing apparatus on the basis of a value of the calculated airflow volume and a value of the first static pressure. a housing that is formed of a resin material, said housing constituting an air duct with an air inlet and an air outlet, the air inlet being configured to take in air, the air outlet being configured to send out the taken air; an opening member installed inside the air duct of the housing, the opening member including an opening allowing the air taken from the air inlet to pass therethrough; pressure sensors (5a, 5b) configured to measure air pressures before and after the air passes through the opening member in the air duct; a variable orifice provided on the opening member to enlarge or contract the size of the diameter of the opening of the opening member; a display; a control unit coupled to the pressure sensors (5a, 5b); and a straightening grid located in the air duct of the housing and configured to straighten the air taken from the air inlet of the housing; wherein: the pressure sensors (5a, 5b) are configured to measure a first static pressure, a second static pressure, and a third static pressure, the first static pressure being air pressure from the air inlet of the housing to the straightening grid in the air duct of the housing, the second static pressure being air pressure from the straightening grid to the opening member, the third static pressure being air pressure after the air has passed through the opening member, and the control unit is configured: to calculate the airflow volume and a static pressure of the wind-blowing apparatus using measurement values of the air pressures before and after the air passes through the opening member; to calculate the airflow volume on the basis of a differential pressure between the second static pressure and the third static pressure; to display the calculated airflow volume and static pressure on the display; and to calculate a ventilation resistance of the wind-blowing apparatus on the basis of a value of the calculated airflow volume and a value of the first static pressure. the pressure sensors (5a, 5b) are configured to measure a first static pressure, a second static pressure, and a third static pressure, the first static pressure being air pressure from the air inlet of the housing to the straightening grid in the air duct of the housing, the second static pressure being air pressure from the straightening grid to the opening member, the third static pressure being air pressure after the air has passed through the opening member, and the control unit is configured: to calculate the airflow volume and a static pressure of the wind-blowing apparatus using measurement values of the air pressures before and after the air passes through the opening member; to calculate the airflow volume on the basis of a differential pressure between the second static pressure and the third static pressure; to display the calculated airflow volume and static pressure on the display; and to calculate a ventilation resistance of the wind-blowing apparatus on the basis of a value of the calculated airflow volume and a value of the first static pressure. to calculate the airflow volume and a static pressure of the wind-blowing apparatus using measurement values of the air pressures before and after the air passes through the opening member; to calculate the airflow volume on the basis of a differential pressure between the second static pressure and the third static pressure; to display the calculated airflow volume and static pressure on the display; and to calculate a ventilation resistance of the wind-blowing apparatus on the basis of a value of the calculated airflow volume and a value of the first static pressure.