A sustained release pheromone preparation for controlling a pest insect contains, as sex pheromone components, an unsaturated aliphatic acetate and an unsaturated aliphatic alcohol having a structure where the acetyl group of the acetate is replaced with a hydrogen atom, wherein a ratio between the acetate and the alcohol in the mixture solution contained in the sustained release pheromone preparation can be kept constant throughout the effective action period. More specifically, the preparation includes a mixture solution containing the unsaturated aliphatic acetate and the unsaturated aliphatic alcohol in a weight ratio of 10:90 to 99.5 to 0.5 and a container for enclosing the mixture solution, the container containing, as at least a part of the container, a membrane of a polyester corresponding to Formula (I) below, a copolymer thereof, or a polymer blend of the polyester or copolymer with a biodegradable polyester.
