To stable and reliably detect a vortex signal even under a high static pressure with an inexpensive structure and a satisfactory S/N by integrally forming the connecting part of a force receiving body and a measuring conduit as a body unit, and forming a thin annular pressure seal fulcrum body on the circumference of the force receiving body in the connecting part.

Since thin annular pressure seal fulcrum body 34 is integrally formed in a clearance between the circumferential surface part of a columnar force receiving body 32 and a measuring conduit 33, an alternating lift Fa generated in the force receiving body 32 can be stable and reliably taken out of the measuring conduit 33 from a fluid to be measured of high static pressure. Since the center part and circumference of the pressure seal fulcrum body 34 are supported by the rigid force receiving body 32 and by the measuring conduit 33, respectively, the thickness can be reduced even to the fluid to be measured of high static pressure. Since the rotating spring constant of the fulcrum body 34 can be thus minimized, the signal to be taken out through the force receiving body 32 can be increased to improve S/N. The conduit 33 has no clearance hole and is free from accumulation or blocking of a solid since the fulcrum body 34 is formed on the inner wall surface of the measuring pipe line 33, and a highly reliable measurement can be performed.