A rotating machine system comprising: a rotating machine that is configured to pressurize or depressurize a gaseous fluid and includes a casing in which a rotor, and a housing chamber housing the rotor are provided; and an abnormality treatment apparatus for the rotating machine, wherein the rotating machine includes: a sensor configured to output a signal upon detecting an event caused by contact of a rotor of the rotating machine during rotation of the rotor; and a control unit for executing, based on reception of the signal output from the sensor, controlling successive reduction of a number of rotations of the rotor, controlling successive liquid injection into the housing chamber of the rotor, and controlling successive reduction of a discharge pressure of the rotating machine, the discharge pressure being generated based on pressurizing the gaseous fluid in the housing chamber, characterized in that the sensor of the abnormality treatment apparatus for the rotating machine is attached to the casing, wherein the control unit is configured to execute controlling the reduction of the number of rotations of the rotor and controlling the liquid injection simultaneously, or to execute controlling the liquid injection after execution of controlling the reduction of the number of rotations of the rotor. a rotating machine that is configured to pressurize or depressurize a gaseous fluid and includes a casing in which a rotor, and a housing chamber housing the rotor are provided; and an abnormality treatment apparatus for the rotating machine, wherein the rotating machine includes: a sensor configured to output a signal upon detecting an event caused by contact of a rotor of the rotating machine during rotation of the rotor; and a control unit for executing, based on reception of the signal output from the sensor, controlling successive reduction of a number of rotations of the rotor, controlling successive liquid injection into the housing chamber of the rotor, and controlling successive reduction of a discharge pressure of the rotating machine, the discharge pressure being generated based on pressurizing the gaseous fluid in the housing chamber, a sensor configured to output a signal upon detecting an event caused by contact of a rotor of the rotating machine during rotation of the rotor; and a control unit for executing, based on reception of the signal output from the sensor, controlling successive reduction of a number of rotations of the rotor, controlling successive liquid injection into the housing chamber of the rotor, and controlling successive reduction of a discharge pressure of the rotating machine, the discharge pressure being generated based on pressurizing the gaseous fluid in the housing chamber, controlling successive reduction of a number of rotations of the rotor, controlling successive liquid injection into the housing chamber of the rotor, and controlling successive reduction of a discharge pressure of the rotating machine, the discharge pressure being generated based on pressurizing the gaseous fluid in the housing chamber, characterized in that the sensor of the abnormality treatment apparatus for the rotating machine is attached to the casing, wherein the control unit is configured to execute controlling the reduction of the number of rotations of the rotor and controlling the liquid injection simultaneously, or to execute controlling the liquid injection after execution of controlling the reduction of the number of rotations of the rotor. to execute controlling the reduction of the number of rotations of the rotor and controlling the liquid injection simultaneously, or to execute controlling the liquid injection after execution of controlling the reduction of the number of rotations of the rotor.