A superconducting magnet device-monitoring system includes detecting unit,
remaining amount estimating unit, and output unit. The detecting unit
detects a remaining amount of liquid helium, in which a superconducting
coil is immersed stored in a liquid helium container of a superconducting
magnet device. The remaining amount estimating unit calculates an
estimated remaining amount, which shows an estimated value of the
remaining amount, on the basis of the remaining amount of liquid helium
preliminarily detected by the detecting unit. The output unit outputs
monitoring information on the superconducting magnet device on the basis
of the detected remaining amount and estimated remaining amount of liquid
helium.