In the 1st report pressure fluctuation at each point in the duct was measured and analyzed. In the present study pressure fluctuations at two points along the duct were simultaneously measured and correlated statistically in the forms of correlation factors and coherences. Thereby the propagation of the pressure fluctuation was investigated. The variation of a pseudo-shock had two main frequencies, high and low ones. The former, the vibration of the air column in the divergent passage propagated upstream as a pressure wave, while the latter propagated covectionally with the main flow.