K 2 NiF 4 -type (Ca 1 - x Nd 1 + x )CoO 4 - δ (0.0=<x=<0.2) was synthesized and found to have a tetragonal structure with a space group I4/mmm. The Rietveld method indicates that distortion in the CoO 6 octahedron decreases gradually with increasing x. Although (Ca 1 - x Nd 1 + x )CoO 4 - δ is paramagnetic above 80K, the (1/χ)-T curve does not follow the Curie-Weiss law. (Ca 1 - x Nd 1 + x )CoO 4 - δ is an n-type semiconductor, and its thermopower varies linearly with temperature. The X-ray photoelectron spectroscopy measurement indicates that the binding energy of the Co 2p 3 / 2 level shifts toward the high binding energy site with increasing Co 2 + ion content. The electrical property of (Ca 1 - x Nd 1 + x )CoO 4 - δ is explained using the model of transport by activated hopping of carriers. Since the gradual increase in the Co-O(1) distance prevents electron transfer in the Co 2 + -O(1)-Co 3 + path, both the electrical resistivity and the activation energy increase with increasing x.