PURPOSE: To find a wind direction, wind velocity, wind energy density and its time integral value by fixing a wind receiving body, symmetric on a perpendicular axis, on a fixed base by a flexible perpendicular support axis and then by providing a strain measuring detector to the intermediate part of the support axis.

CONSTITUTION: Wind receiving hollow body 1 axis-symmetric on a perpendicular axis is supported by flexible support axis 2 of circular section and part 3 of support axis 2 is worked in an equilateral polygon; and strain gauge 4 is stuck to each surface of it by adhesives and the support axis is fixed on the ground with the stuck surfaces facing to the four cardinal points of the compass. Resistance values of strain gauge 4 facing to the north, south, west and east are denoted as RNWRE and beat frequencies fNS and fWE extracted by mixing frequencies of CR oscillating circuits, e.g. fN and fs; and fW and fE are further vector-mixed to obtain frequency (f). Here, since frequency (f) corresponds to drag D by a vector-mixed wind, incorporating a program, converting frequency (f) into drag D, in an operator makes it possible to extract, display and record drag D as an output signal.