Abstract: Objects are to provide: a fusion protein capable of binding to lipid droplets while having an enzymatic activity to synthesize a hydrophobic compound; a method for producing a substance including accumulating a hydrophobic compound in lipid droplets using the fusion protein; a vector which can enhance production of a hydrophobic compound when it is introduced into cells using genetic recombination techniques; and a transgenic cell into which the vector or a gene coding for the fusion protein has been introduced. The present disclosure relates to a fusion protein having an amino acid sequence (first amino acid sequence) capable of binding to lipid droplets, and an amino acid sequence (second amino acid sequence) having an enzymatic activity to synthesize a hydrophobic compound, with the enzymatic activity of the second amino acid sequence being maintained.