A flow rate measurement apparatus includes first and second transducers provided at different positions in a longitudinal direction of a pipe, the at least two transducers including first and second transducers. The flow rate measurement apparatus further includes a transmitter and receiver. The transmitter transmits a transmission signal, which is an ultrasonic signal having a band wider than the ultrasonic signal, or a plurality of ultrasonic signals having a plurality of different frequency ranges. The receiver separates a target signal passing through a fluid from the received signal by utilizing that an attenuation rate of the ultrasonic signal in the fluid in a predetermined frequency band is different from an attenuation rate of the ultrasonic signal in the pipe in the frequency band, and measures a flow rate based on a separated target signal.