Recently, the treatment of a large quantity of expanded polystyrene (EPS) waste that accumulates in wholesale markets, etc., has become a problem, while the demand for EPS containers has increased as a distribution material for agricultural and marine products. In this study, a questionnaire survey and field study were carried out in order to determine the generation rate of the EPS waste and the method of processing, intensions of resource recycling, etc. for domestic central wholesale markets. The development of a volume reduction method and resource recycling method of EPS containers is also required. The effect of 3 kinds of volume reduction methods was then examined. A low-temperature petrochemical method involving a pyrolysis treatment at 200°C or less was developed. As a result, depolymerization could possibly reduce the number average molecular weight to less than 5000.