A rotary compressor includes: a vertically-positioned airtight compressor housing having an upper section including a discharge portion of a refrigerant, and a lower section including an inlet unit of the refrigerant and storing lubricant oil; a compressing unit, disposed in the lower section, compressing the refrigerant sucked in via the inlet unit and discharging the refrigerant from the discharge portion; a motor, disposed in the upper section, driving the compressing unit via a rotation shaft; and an accumulator attached to the compressor housing and connected to the inlet unit. Inside the accumulator and/or the compressor housing, silicon dioxide having a crystal structure containing a vacancy with a diameter equal to or less than a diameter of a water molecule or a composite including silicon dioxide having a crystal structure containing a vacancy with a diameter equal to or less than that of the water molecule is placed.