A monitoring apparatus comprising: a measured data acquisition unit configured to acquire time-series measured data including one or more measured values output from one or more sensors installed in a system to be monitored; a model acquisition unit configured to acquire a prediction model that generates predicted data including one or more predicted values predicted to be output from the one or more sensors at a first time based on the measured data at or before the first time; a past data acquisition unit configured to acquire, as a past data, data including information on a past distribution representing a distribution of a measured value in a first period, with respect to time-series data including one or more measured values output from the one or more sensors before the time-series measured data in a time direction, the first period being a period of training data used to train the prediction model; a predicted data generation unit configured to generate time-series predicted data based on the time-series measured data and the prediction model; and an image generation unit configured to generate, for a first sensor among the one or more sensors, a displayed image including a measured value graph representing a temporal change in a measured value included in the time-series measured data in a second period that is a period after the first period, a predicted value graph representing a temporal change in a predicted value included in the time-series predicted data in the second period, the monitoring apparatus being characterized in that the displayed image further includes: the past distribution in the first period and a measurement distribution representing a distribution of the measured value included in the time-series measured data in the second period. period. a measured data acquisition unit configured to acquire time-series measured data including one or more measured values output from one or more sensors installed in a system to be monitored; a model acquisition unit configured to acquire a prediction model that generates predicted data including one or more predicted values predicted to be output from the one or more sensors at a first time based on the measured data at or before the first time; a past data acquisition unit configured to acquire, as a past data, data including information on a past distribution representing a distribution of a measured value in a first period, with respect to time-series data including one or more measured values output from the one or more sensors before the time-series measured data in a time direction, the first period being a period of training data used to train the prediction model; a predicted data generation unit configured to generate time-series predicted data based on the time-series measured data and the prediction model; and an image generation unit configured to generate, for a first sensor among the one or more sensors, a displayed image including a measured value graph representing a temporal change in a measured value included in the time-series measured data in a second period that is a period after the first period, a predicted value graph representing a temporal change in a predicted value included in the time-series predicted data in the second period, the monitoring apparatus being characterized in that the displayed image further includes: the past distribution in the first period and a measurement distribution representing a distribution of the measured value included in the time-series measured data in the second period. period.