A centrifugal compressor, comprising: a casing; a compression mechanism provided inside the casing; a flow rate regulation valve that is provided inside the casing, includes a plurality of blades, and is configured to regulate a flow rate of air sucked into the casing by directions of the plurality of blades; a conversion mechanism that is provided outside the casing and is configured to change an output of an actuator into rotation motion changing the directions of the plurality of blades of the flow rate regulation valve according to an output of the actuator; and a cover that covers surroundings of the conversion mechanism to house the conversion mechanism and in which an air reservoir to prevent dew condensation on the conversion mechanism through supply of dry air to an inside of the cover is formed, wherein a portion of compressed air compressed by the compression mechanism is supplied as the dry air to form the air reservoir for prevention of dew condensation, wherein the compression mechanism includes a first compression section that compresses the sucked air, a second compression section that further compresses the compressed air compressed by the first compression section, a connection piping through which the compressed air compressed by the first compression section flows toward the second compression section, and a return piping that makes the connection piping and the cover communicate with each other and causes a portion of the compressed air flowing through the connection piping to flow toward the inside of the cover, wherein the connection piping includes a cooling dehumidifier (18, 19) that cools and dehumidifies the compressed air compressed by the first compression section, and the return piping causes a portion of the compressed air that has passed through the cooling dehumidifier (18,19) to flow toward the inside of the cover. a casing; a compression mechanism provided inside the casing; a flow rate regulation valve that is provided inside the casing, includes a plurality of blades, and is configured to regulate a flow rate of air sucked into the casing by directions of the plurality of blades; a conversion mechanism that is provided outside the casing and is configured to change an output of an actuator into rotation motion changing the directions of the plurality of blades of the flow rate regulation valve according to an output of the actuator; and a cover that covers surroundings of the conversion mechanism to house the conversion mechanism and in which an air reservoir to prevent dew condensation on the conversion mechanism through supply of dry air to an inside of the cover is formed, wherein a portion of compressed air compressed by the compression mechanism is supplied as the dry air to form the air reservoir for prevention of dew condensation, wherein the compression mechanism includes a first compression section that compresses the sucked air, a second compression section that further compresses the compressed air compressed by the first compression section, a connection piping through which the compressed air compressed by the first compression section flows toward the second compression section, and a return piping that makes the connection piping and the cover communicate with each other and causes a portion of the compressed air flowing through the connection piping to flow toward the inside of the cover, wherein the connection piping includes a cooling dehumidifier (18, 19) that cools and dehumidifies the compressed air compressed by the first compression section, and the return piping causes a portion of the compressed air that has passed through the cooling dehumidifier (18,19) to flow toward the inside of the cover.