Abstract: The present invention relates to a device useful for measuring the flow rate of cryogenic liquids flowing through a tube, which comprises two coaxial tubes integrated at both ends by means such as plugs, the space between the coaxial tubes being air-free and filled with insulating material, the said coaxial tubes being provided at the bottom walls with a segmental opening with sealed ends in such a manner so as to accommodate a closed ended hollow cylinder having a matching inner surface profile as that of inner surface of the said tube, the outer surface of the said hollow cylinder having insulating block fixed onto it one end of a conducting strip, the strip being rotatably fixed at its middle portion by means such as a hinge, support and fixed frame in such a manner that the inner surface of the cylinder flushes with the inner wall of the tube and allows lateral movement of the said cylinder due to drag force of cryogenic liquid flow, the said frame having two insulators fixed onto it to support a stretche