A monitoring system comprising: a nozzle steam trap including a supply portion into which water vapor is supplied, and a discharge portion which discharges liquid water contained in the water vapor; a temperature measurer that measures a temperature of the discharge portion; a transmitter that transmits temperature information containing the temperature measured by the temperature measurer; a receiver that receives the temperature information; a determiner that determines whether an abnormality is present in the nozzle steam trap based on the temperature information; and a notifier that issues a notice when the determiner determines that the abnormality is present; wherein the nozzle steam trap has: a nozzle including a nozzle hole from which the water vapor and the liquid water are jetted; a water storage portion that stores the liquid water jetted from the nozzle hole and includes an opening; and a channel that guides the liquid water to the discharge portion from the opening, and wherein, with a first discharge-side reference temperature (T e1) lower than a boiling point of the water and a second discharge-side reference temperature (T e2) higher than the boiling point of the water being set for the discharge portion, the determiner determines that the abnormality is present when the temperature of the discharge portion contained in the temperature information is lower than the first discharge-side reference temperature or higher than the second discharge-side reference temperature. a nozzle steam trap including a supply portion into which water vapor is supplied, and a discharge portion which discharges liquid water contained in the water vapor; a temperature measurer that measures a temperature of the discharge portion; a transmitter that transmits temperature information containing the temperature measured by the temperature measurer; a receiver that receives the temperature information; a determiner that determines whether an abnormality is present in the nozzle steam trap based on the temperature information; and a notifier that issues a notice when the determiner determines that the abnormality is present; wherein the nozzle steam trap has: a nozzle including a nozzle hole from which the water vapor and the liquid water are jetted; a water storage portion that stores the liquid water jetted from the nozzle hole and includes an opening; and a channel that guides the liquid water to the discharge portion from the opening, and a nozzle including a nozzle hole from which the water vapor and the liquid water are jetted; a water storage portion that stores the liquid water jetted from the nozzle hole and includes an opening; and a channel that guides the liquid water to the discharge portion from the opening, and wherein, with a first discharge-side reference temperature (T e1) lower than a boiling point of the water and a second discharge-side reference temperature (T e2) higher than the boiling point of the water being set for the discharge portion, the determiner determines that the abnormality is present when the temperature of the discharge portion contained in the temperature information is lower than the first discharge-side reference temperature or higher than the second discharge-side reference temperature.