In a position detecting apparatus, digital signals in the presence of excitation signals are corrected by digital signals in the absence of excitation signals which are off-set values generated by each components of this postiion detecting apparatus. It therefore eliminates troublesome adjustment by variable resistors, and achieves precise position detection at any time without errors. Furthermore, since signals in the direction opposite to exciting signals are applied to the resolver upon the completion of excitation, the output of the resolver quickly becomes stable in the non-excited state, and off-set values are measured at a high speed.