There are provided a catalyst composition for producing hydrocarbons and a method for producing hydrocarbons which exhibit a high CO conversion rate, generates minimal amount of gaseous components, and is also capable of efficiently obtaining, from a syngas, a gasoline fraction which is selective for and rich in the components having a high octane number, such as aromatic, naphthenic, olefinic and branched paraffinic hydrocarbons, by using a Fischer-Tropsch synthesis catalyst that contains at least one type of metal exhibiting activity in Fischer-Tropsch reaction and manganese carbonate and a zeolite serving as a solid acid.