To provide a robot capable of suppressing lowering of detection accuracy of a voltage value caused by a time deviation between voltage of a first phase and voltage of a second phase of AC power supply detected by a control means without complicating a circuitry.

A control circuit 26 reads voltage waveform data preceding by almost one period from a present time point and voltage waveform data further preceding the data by one-sampling, of voltage waveform data stored in a memory for every prescribed sampling period, determines inclinations of voltage of R phase and S phase at a point of time preceding by almost one period from the present time point based on a difference between voltage values of the voltage waveform data for each phase, and estimates inclination of voltage of each phase at the present time point from the inclinations. The control circuit 26 controls switching of a multiplexer 31 to sample voltage of the phase having larger estimated inclination of voltage first and continuously sample voltage of the other phase.

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