An alkyl tin compound having an alkyl group bonded to a tin atom, wherein the alkyl group is a branched alkyl or cyclic group-substituted alkyl group, the branched alkyl group being an alkyl group branched at at least one carbon atom of the first to third carbon atoms counting from the tin atom, and the cyclic group-substituted alkyl group being an alkyl group having a cyclic group bonded at at least one carbon atom of the first to third carbon atoms counting from the tin atom.