A monitoring device includes an estimation unit, a detection unit, and a correction unit. The estimation unit estimates a degree of degradation of a moving object based on at least an amount of movement of the moving object. The detection unit detects an environment state of the moving object at a time when the moving object is moved, as operation parameter values including an amount of an operation at a time when an operation unit is operated and an operation time. The correction unit corrects the degree of degradation, which is estimated by the estimation unit, based on the operation parameter values detected by the detection unit.