<p>Sex pheromones of mealybugs are reported from more than 20 species and have generally been shown to be monoterpene alcohols esterified with short-chain carboxylic acids. Here, however, we discovered and isolated an alcohol without an acid moiety as a pheromone compound released from adult females of the papaya mealybug, <i>Paracoccus marginatus</i>. By means of gas chromatography – mass spectrometry and nuclear magnetic resonance spectroscopy analyses, the structure was identified to be <i>trans</i>-2-(2-isopropenyl-1-methylcyclobutyl)ethanol, a monoterpene with a unique cyclobutene skeleton, commonly known as fragranol. We then completely separated synthetic (±)-fragranol into each enantiomer by means of preparative high-performance liquid chromatography using a chiral resolution column, and (−)-(1<i>S</i>,2<i>S</i>)-fragranol was definitely confirmed to be the natural pheromone and to attract many males in the field when used as a pheromone trap lure. (±)-Fragranol showed attractiveness comparable to that of the pure (−)-(1<i>S</i>,2<i>S</i>)-enantiomer. This study provides not only useful information for the monitoring and management of <i>P</i>. <i>marginatus</i> but also an interesting exception underlining the great diversity of mealybug pheromone structures.</p>