A monitoring device comprising: a physical quantity acquisition section for acquiring physical quantities indicative of a state of a monitoring target device; an abnormality determination section for determining, in accordance with whether or not the physical quantities acquired by the physical quantity acquisition section fall within a predetermined range, whether or not there is an abnormality; characterized by an abnormal waveform data generation section for, in a case where the abnormality determination section determines that there is an abnormality, generating abnormal waveform data indicative of a change over time in the physical quantities acquired during an abnormal waveform period containing at least a period from a point in time at which the abnormality determination section determines that there is an abnormality to a point in time at which a predetermined accumulation time elapsed; a reporting section for causing a display section to display an abnormal waveform indicated by the abnormal waveform data generated by the abnormal waveform data generation section; and a normal waveform data management section for managing normal waveform data indicative of a change over time in the physical quantities in a normal state, the normal waveform data management section being adapted to generate the normal waveform data by extracting, from the physical quantities acquired by the physical quantity acquisition section during a period from a predetermined time before a current point in time to the current point in time, physical quantities for which the abnormality determination section continuously determines for a predetermined time that there is no abnormality, and the reporting section being adapted to cause the abnormal waveform and a normal waveform indicated by the normal waveform data to be displayed on a single screen of the display section. a physical quantity acquisition section for acquiring physical quantities indicative of a state of a monitoring target device; an abnormality determination section for determining, in accordance with whether or not the physical quantities acquired by the physical quantity acquisition section fall within a predetermined range, whether or not there is an abnormality; characterized by an abnormal waveform data generation section for, in a case where the abnormality determination section determines that there is an abnormality, generating abnormal waveform data indicative of a change over time in the physical quantities acquired during an abnormal waveform period containing at least a period from a point in time at which the abnormality determination section determines that there is an abnormality to a point in time at which a predetermined accumulation time elapsed; a reporting section for causing a display section to display an abnormal waveform indicated by the abnormal waveform data generated by the abnormal waveform data generation section; and a normal waveform data management section for managing normal waveform data indicative of a change over time in the physical quantities in a normal state, the normal waveform data management section being adapted to generate the normal waveform data by extracting, from the physical quantities acquired by the physical quantity acquisition section during a period from a predetermined time before a current point in time to the current point in time, physical quantities for which the abnormality determination section continuously determines for a predetermined time that there is no abnormality, and the reporting section being adapted to cause the abnormal waveform and a normal waveform indicated by the normal waveform data to be displayed on a single screen of the display section.