A real time clock for outputting data indicating a time of day includes: an event detection circuit for detecting that an event detection signal has been inputted from outside; a timing circuit for generating the time-of-day data according to a signal outputted from an oscillator circuit; a memory; and a control circuit for, if the event detection circuit detects input of the event detection signal, recording event data in the memory, the event data including additional data indicating an operating state of the real time clock and the time-of-day data generated by the timing circuit.