Provided is a counter unit capable of supporting any output apparatus of single-phase output, two-phase output, or three-phase output without waste. A counter unit (10) is provided with: a plurality of signal input terminals to which pulse signals outputted from a plurality of external output apparatuses (50) are respectively inputted; input circuits (21a to 21f) respectively connected to the plurality of signal input terminals; a single-phase counter (13) that performs count on the basis of a single-phase pulse signal, and a multi-phase counter (15) that performs count on the basis of a multi-phase pulse signal; and a switching part (16) that switches whether the input circuits (21a to 21f) are connected to the single-phase counter (13) or the multi-phase counter (15).