The pure rotational spectrum of the (NCl)-N-14-Cl-35 radical in the first electronically excited a (1) Delta state was detected by microwave spectroscopy. The NCl radical was produced by a de-glow discharge of an N-2, and Cl-2 mixture between 175-210 K. Seven rotational transitions for v=0 and five for v=1, showing hyperfine structures due to the nitrogen and chlorine nuclei, were observed in the 162-404 GHz region. The rotational, centrifugal distortion, and hyperfine coupling constants including nuclear spin-rotation coupling constant of the chlorine nucleus were determined accurately by a least-squares analysis of the measured frequencies. The equilibrium structural parameters were derived and discussed.