PROBLEM TO BE SOLVED: To provide a method for producing an N,N-dialkylhomofarnesic acid amide which is a precursor of (±)-3a,6,6,9a-tetramethyldodecahydronaphtho[2,1-b]furan useful as a fragrance with a high raw material recovery rate, high purity and high yield and a method for producing (±)-3a,6,6,9a-tetramethyldodecahydronaphtho[2,1-b]furan.SOLUTION: There is provided a method for producing an N,N-dialkylhomofarnesic acid amide by reacting nerolidol with N,N-dialkylformamide dimethyl acetal under conditions where the N,N-dialkylformamide dimethyl acetal is refluxed, wherein the molar ratio of the N,N-dialkylformamide dimethyl acetal to nerolidol is 1.5 to 3.