Abstract: In the pole and line fishing for mackerel to make them lure long in the illumination zone of attracting fish lamps, it is necessary to scatter ground baits continuously on the illuminated water until the fishing end. Thus, the effects of ground baits and attracting fish lamps on the catch of the fishing may be very serious. In this paper the effects were investigated by the comparison between the catch of the boats based on the same harbour and the factors affecting on the catch, using the logbooks of the fishing boats operating in the sea near Boso Peninsula, Chiba Prefecture. The results obtained are as follows: the consumption of ground baits has the most close relation to the catch compared with other factors, such as the tonnage of boats, the number of crew and the power of generators, and simultaneously, from the relation between fishing ability and light intensity (Fig. 3), a higher intensity of the lamps over 300 watts per an angler seems to be disadvantage for the fishing.