To effectively remove a high frequency component from a reference side area pressure inputted to a differential pressure measuring part.
In the differential pressure measuring device having a reference pressure input part (a) for inputting the area pressure Pi of a reference area 2 through a reference side pressure guide passage ri having one end opened to the reference area 2, a comparison pressure input part (b) for inputting the area pressure Ps of a comparison area 1 through a comparison side pressure guide passage rs having one end opened to the comparison area 1; and a differential pressure measuring part (c) for measuring the difference ΔP of both the area pressures Pi, Ps inputted to the input parts (a), (b), the reference side guide pressure passage ri has a throttle part X for contracting the pressure guide area sectional area in one position in the longitudinal direction thereof and a cushioning capacity part Y situated on the side closer to the reference pressure input part (a) from the throttle part X and having a pressure guide passage sectional area larger than the pressure guide passage sectional area in the throttle part X.
SUKEMIYA KENJI
OU CHIYUUEKI
