A bathroom exhaust fan switching device for turning on a bathroom exhaust fan automatically upon start of a shower includes a switching module, which can be installed in a bathroom in-line with the bathroom exhaust fan, which is operationally engaged to an electrical circuit. The switching module comprises a transducer, a relay, and a microprocessor. The transducer converts sound into an electrical signal. The relay is operationally engaged to the electrical circuit. The microprocessor, which is operationally engaged to the transducer and the relay, is programmed to recognize a sound signature of a shower in the bathroom to the exclusion of sound signatures of other water fixtures in the bathroom. The microprocessor actuates the relay upon receipt of an electrical signal from the transducer bearing the sound signature of the shower so that the bathroom exhaust fan is powered on to remove moist air from the bathroom.