A method for producing an -dienal compound, comprising the steps of: metalizing a terminal alkyne of an alkynal acetal compound represented by formula: wherein n is an integer of from 2 to 11, and R 1 and R 2 each independently represents a monovalent hydrocarbon group having from 1 to 10 carbon atoms, or R 1 and R 2 are coupled together to form a divalent hydrocarbon group having from 2 to 10 carbon atoms, through a metalation reaction of the alkynal acetal compound to obtain an organic metal compound represented by formula: wherein M represents a cationic moiety; reacting the organic metal compound with ethylene oxide through an addition reaction to obtain a hydroxyalkynal acetal compound represented by formula: reducing the hydroxyalkynal acetal compound through a reduction reaction of converting a triple bond of the hydroxyalkynal acetal compound into an -double bond to obtain an -hydroxyalkenal acetal compound represented by formula: converting a hydroxyl group of the -hydroxyalkenal acetal compound into a leaving group X through a functional group conversion reaction of the -hydroxyalkenal acetal compound to obtain an -alkenal acetal compound having the leaving group X represented by formula: wherein X represents a leaving group; eliminating HX from the -alkenal acetal compound having the leaving group X through an elimination reaction of the -alkenal acetal compound to obtain an -dienal acetal compound represented by formula: and hydrolyzing the -dienal acetal compound through a hydrolysis reaction of converting an acetal of the -dienal acetal compound into an aldehyde to obtain the -dienal compound represented by formula: metalizing a terminal alkyne of an alkynal acetal compound represented by formula: wherein n is an integer of from 2 to 11, and R 1 and R 2 each independently represents a monovalent hydrocarbon group having from 1 to 10 carbon atoms, or R 1 and R 2 are coupled together to form a divalent hydrocarbon group having from 2 to 10 carbon atoms, through a metalation reaction of the alkynal acetal compound to obtain an organic metal compound represented by formula: wherein M represents a cationic moiety; wherein n is an integer of from 2 to 11, and R 1 and R 2 each independently represents a monovalent hydrocarbon group having from 1 to 10 carbon atoms, or R 1 and R 2 are coupled together to form a divalent hydrocarbon group having from 2 to 10 carbon atoms, through a metalation reaction of the alkynal acetal compound to obtain an organic metal compound represented by formula: wherein M represents a cationic moiety; reacting the organic metal compound with ethylene oxide through an addition reaction to obtain a hydroxyalkynal acetal compound represented by formula: reducing the hydroxyalkynal acetal compound through a reduction reaction of converting a triple bond of the hydroxyalkynal acetal compound into an -double bond to obtain an -hydroxyalkenal acetal compound represented by formula: converting a hydroxyl group of the -hydroxyalkenal acetal compound into a leaving group X through a functional group conversion reaction of the -hydroxyalkenal acetal compound to obtain an -alkenal acetal compound having the leaving group X represented by formula: wherein X represents a leaving group; eliminating HX from the -alkenal acetal compound having the leaving group X through an elimination reaction of the -alkenal acetal compound to obtain an -dienal acetal compound represented by formula: and hydrolyzing the -dienal acetal compound through a hydrolysis reaction of converting an acetal of the -dienal acetal compound into an aldehyde to obtain the -dienal compound represented by formula: