Targeting an insect pest having a carboxylic acid compound as a pheromone substance, provided is a sustained release pheromone preparation enabling a high amount of pheromone to be released during the control period. More specifically, provided is a sustained release pheromone preparation, comprising: a carboxylic acid compound to be released, and an ethylene-vinyl acetate copolymer membrane through which the carboxylic acid compound can permeate, wherein the preparation is targeted for an insect pest having the carboxylic acid compound as a pheromone substance.