A real-time clock module includes an oscillation circuit, a storage unit that stores adjustment data used to adjust an oscillation frequency of the oscillation circuit, a data abnormality determination circuit that compares first data based on the adjustment data with second data based on the adjustment data to determine whether or not at least one of the first data and the second data is abnormal, and a flag register that holds a data abnormality flag in which a first value indicating that the first data and the second data are normal, or a second value indicating that at least one of the first data and the second data is abnormal is set, based on a signal from the data abnormality determination circuit.