Compressor

A compressor comprising:

• a casing that is horizontally elongated or vertically elongated;
• an electric motor housed in the casing;
• a compression mechanism configured to be driven by the electric motor to compress a refrigerant;
• a plurality of supporting portions arranged between an inner peripheral surface of the casing and an outer surface of the electric motor, the plurality of supporting portions being configured to support the electric motor in the casing;
• and
• a reduction mechanism provided in the casing,
• a plurality of predetermined spaces being formed between the inner surface of the casing and the outer surface of the electric motor, the plurality of predetermined spaces being separated by the supporting portions, and
• the reduction mechanism being configured to reduce a resonant mode that is excited in the plurality of predetermined spaces by operation of the electric motor.