A steam-using facility monitoring system configured to monitor a steam-using facility that includes a steam supply unit that is supplied with steam, a steam-using unit that uses supplied steam, and a steam discharge unit that discharges steam after use, the steam-using facility monitoring system comprising: a temperature sensor (21b, 23b) that is a trap temperature sensor configured to detect a temperature of a steam trap provided in the steam discharge unit and/or a steam temperature sensor configured to detect a temperature of steam flowing into the steam trap; and a pressure sensor configured to detect a pressure of steam flowing into the steam trap, characterized in that the steam-using facility monitoring system comprises a computation unit for determining that there is an occurrence of an abnormality or a sign of the abnormality in the steam trap depending on a deviation of(i) a temperature detection value obtained by the temperature sensor and/or statistical temperature data obtained by performing statistical processing on the temperature detection value from a predetermined criterion thereof and (ii) a pressure detection value obtained by the pressure sensor and/or statistical pressure data obtained by performing statistical processing on the pressure detection value from a predetermined criterion thereof, and the computation unit is configured to determine that there is an occurrence of an abnormality or there is a sign of the abnormality in a steam supply valve that is provided in the steam supply unit when (i) the pressure detection value and/or the statistical pressure data deviates from a predetermined criterion thereof and (ii) the temperature detection value and the statistical temperature data satisfy predetermined criteria thereof. a temperature sensor (21b, 23b) that is a trap temperature sensor configured to detect a temperature of a steam trap provided in the steam discharge unit and/or a steam temperature sensor configured to detect a temperature of steam flowing into the steam trap; and a pressure sensor configured to detect a pressure of steam flowing into the steam trap, characterized in that the steam-using facility monitoring system comprises a computation unit for determining that there is an occurrence of an abnormality or a sign of the abnormality in the steam trap depending on a deviation of(i) a temperature detection value obtained by the temperature sensor and/or statistical temperature data obtained by performing statistical processing on the temperature detection value from a predetermined criterion thereof and (ii) a pressure detection value obtained by the pressure sensor and/or statistical pressure data obtained by performing statistical processing on the pressure detection value from a predetermined criterion thereof, and the computation unit is configured to determine that there is an occurrence of an abnormality or there is a sign of the abnormality in a steam supply valve that is provided in the steam supply unit when (i) the pressure detection value and/or the statistical pressure data deviates from a predetermined criterion thereof and (ii) the temperature detection value and the statistical temperature data satisfy predetermined criteria thereof. a computation unit for determining that there is an occurrence of an abnormality or a sign of the abnormality in the steam trap depending on a deviation of(i) a temperature detection value obtained by the temperature sensor and/or statistical temperature data obtained by performing statistical processing on the temperature detection value from a predetermined criterion thereof and (ii) a pressure detection value obtained by the pressure sensor and/or statistical pressure data obtained by performing statistical processing on the pressure detection value from a predetermined criterion thereof, and the computation unit is configured to determine that there is an occurrence of an abnormality or there is a sign of the abnormality in a steam supply valve that is provided in the steam supply unit when (i) the pressure detection value and/or the statistical pressure data deviates from a predetermined criterion thereof and (ii) the temperature detection value and the statistical temperature data satisfy predetermined criteria thereof.