Abstract: In an elevator control apparatus, calculations regarding the control of an elevator are performed in a duplexed system including first and second processing portions. A first clock signal from a first clock is input to the first processing portion. A second clock signal from a second clock is input to the second processing portion. The first and second clock signals are input to a clock abnormality detecting circuit. The clock abnormality detecting circuit counts the numbers of pulses of the first and second clock signals, and detects abnormalities in the first and second clock signals from a difference between the numbers of the pulses.