A propagation time measurement device , comprising: a plurality of transducers at different positions with respect to a pipe through which a fluid flows, the plurality of transducers including a first transducer configured to convert a transmission signal as an electrical signal to an acoustic signal and a second transducer configured to receive the acoustic signal transmitted from the first transducer through the fluid in the pipe and convert the received acoustic signal to a reception signal as an electrical signal; and a signal processor configured to remove reverberation from the reception signal and determine a propagation time of the acoustic signal from the first transducer to the second transducer by cross-correlation analysis between the transmission signal and the reception signal from which the reverberation has been removed, wherein the signal processor determines a propagation time of the acoustic signal from the first transducer to the second transducer by cross-correlation analysis between the transmission signal and the reception signal from which the reverberation has yet to be removed, removes, as the reverberation, a signal component at and after a time point based on the determined propagation time, and redetermines the propagation time of the acoustic signal from the first transducer to the second transducer by cross-correlation analysis between the transmission signal and the reception signal from which the reverberation has been removed. a plurality of transducers at different positions with respect to a pipe through which a fluid flows, the plurality of transducers including a first transducer configured to convert a transmission signal as an electrical signal to an acoustic signal and a second transducer configured to receive the acoustic signal transmitted from the first transducer through the fluid in the pipe and convert the received acoustic signal to a reception signal as an electrical signal; and a signal processor configured to remove reverberation from the reception signal and determine a propagation time of the acoustic signal from the first transducer to the second transducer by cross-correlation analysis between the transmission signal and the reception signal from which the reverberation has been removed, wherein the signal processor determines a propagation time of the acoustic signal from the first transducer to the second transducer by cross-correlation analysis between the transmission signal and the reception signal from which the reverberation has yet to be removed, removes, as the reverberation, a signal component at and after a time point based on the determined propagation time, and redetermines the propagation time of the acoustic signal from the first transducer to the second transducer by cross-correlation analysis between the transmission signal and the reception signal from which the reverberation has been removed. determines a propagation time of the acoustic signal from the first transducer to the second transducer by cross-correlation analysis between the transmission signal and the reception signal from which the reverberation has yet to be removed, removes, as the reverberation, a signal component at and after a time point based on the determined propagation time, and redetermines the propagation time of the acoustic signal from the first transducer to the second transducer by cross-correlation analysis between the transmission signal and the reception signal from which the reverberation has been removed. <EOS>