A monitoring system comprising: a detection unit configured to detect that a detection value relating to a power storage system satisfies conditions including a first condition; an identification unit configured to identify a type of fault occurring in the power storage system, in accordance with the detection by the detection unit; and a decision unit configured to decide an operation continuable time of the power storage system after the type of fault is identified, only when the identified type of fault is a specific one, characterised in that the decision unit is configured to compute a remaining life of the power storage system, by subtracting a value according to the identified type of fault, from a standard remaining life corresponding to the years of use of the power storage system up to the present, the first condition includes an insulation resistance value of a cell stack falls below a first reference value, the identification unit is configured to identify, as the type of fault, the number of a cell or cells whose voltage value falls below a second reference value among a plurality of cells of the cell stack whose insulation resistance value falls below the first reference value, in a case where no cell whose voltage value falls below the second reference value is identified, the identification unit is configured to output a request for maintenance, in a case where two or more cells whose voltage value falls below the second reference value are identified, the identification unit is configured to output a stop command for stopping the operation of the power storage system, and in a case where one cell whose voltage value falls below the second reference value is identified, representing the specific one type of fault, the decision unit is configured to decide the operation continuable time of the power storage system. a detection unit configured to detect that a detection value relating to a power storage system satisfies conditions including a first condition; an identification unit configured to identify a type of fault occurring in the power storage system, in accordance with the detection by the detection unit; and a decision unit configured to decide an operation continuable time of the power storage system after the type of fault is identified, only when the identified type of fault is a specific one, characterised in that the decision unit is configured to compute a remaining life of the power storage system, by subtracting a value according to the identified type of fault, from a standard remaining life corresponding to the years of use of the power storage system up to the present, the first condition includes an insulation resistance value of a cell stack falls below a first reference value, the identification unit is configured to identify, as the type of fault, the number of a cell or cells whose voltage value falls below a second reference value among a plurality of cells of the cell stack whose insulation resistance value falls below the first reference value, in a case where no cell whose voltage value falls below the second reference value is identified, the identification unit is configured to output a request for maintenance, in a case where two or more cells whose voltage value falls below the second reference value are identified, the identification unit is configured to output a stop command for stopping the operation of the power storage system, and in a case where one cell whose voltage value falls below the second reference value is identified, representing the specific one type of fault, the decision unit is configured to decide the operation continuable time of the power storage system.