Temperature controller and abnormality determination method

To sufficiently take advantage of the capacity of a heater in a scope for causing no heater damage. A calculation unit obtains, as a temperature-rise rate, a temperature-rise change per unit time in a heater that is measured by a measurement unit. A first detection unit detects that a measured temperature measured by the measurement unit has exceeded a predetermined first value. A second detection unit detects that the temperature-rise rate obtained by the calculation unit has exceeded a predetermined second value. A first measuring unit measures a time in which a state, where the first detection unit detects that the measured temperature has exceeded the first value and the second detection unit detects that the temperature-rise rate has exceeded the second value, continues. A determination unit determines that an abnormality occurs when a time measured by the first measuring unit exceeds a predetermined first time.