To efficiently obtain the subject compound, a flavor ingredient of pear, by subjecting the other ester of trans-2, cis-4-decadienoic acid to an enzymatic ester interchange reaction using a lipase originated from Candida cantarctica in the presence of ethanol.

Stilingia oil containing the other ester of trans-2, cis-4- decadienoic acid which is a plant fat collected from the seeds of Stilingia sebifera, sapium sepiferum or Euphorbiaceeae originated in China is mixed with a lipase originated from Candida cantarctica in the presence of natural ethanol and subsequently subjected to an enzymatic ester interchange reaction under shaking at 20°C for three days to obtain the objective trans-2, cis-4- decadienoic acid ethyl ester, a flavor ingredient of pear, in a high yield.