We have conducted a spectral line survey of the 3 mm band with the 45 m telescope of Nobeyama Radio Observatory toward the L 1157 B1 shocked region, where the blue-shifted component of the bipolar outflow from the protostar IRAS 20386+6751 interacts with the ambient gas. The observed frequency ranges from 78.1 to 115.8 GHz. We have detected 129 spectral lines of 29 molecular species. In addition to various oxygen-bearing organic molecules such as CH3CHO, HCOOCH3, and HCOOH, we have detected a phosphorus-containing molecule PN, a nitrogen-bearing organic molecule NH2 CHO, and a carbon-chain molecule CCS in the shocked region. These results clearly indicate that the L 1157 B1 shocked region is chemically rich, which is probably triggered by evaporation of grain mantles.