The invention provides a repellent to harmful flying insects which comprises as an effective ingredient at least one selected from the group consisting of glycerin fatty acid ester, sorbitan fatty acid ester, acetylated monoglyceride, organic acid monoglyceride, propylene glycol fatty acid ester, polyoxyethylene sorbitan, fatty acid, sucrose fatty acid ester, sorbitan, and soybean oil fatty acid methyl ester a method for repelling harmful flying insects which comprises the step of applying the repellent to a plant to which the insects are harmful.