To provide a mounting structure of a compressor capable of surely preventing deformation or the like of a compressor casing even when the compressor casing is an aluminum cast molded article, by preventing overheating of the compressor casing under high-temperature and high-pressure conditions, reducing the size and weight, and coping with the demand for cost reduction, and an air-conditioning system having the mounting structure.

In the mounting structure of the compressor, fixing bosses provided on the compressor casing are connected and secured to an engine or brackets attached to the engine. The area of a connecting end face of each fixing boss on the engine side is set to be larger than that of the other side end face thereof.