The present invention discloses a method of constructing a non-reactive high frequency constant resistance unit to be used for measuring parameters of quartz crystal units described in U.S. Pat. No. 3,832,631 and U.S. Pat. No. 3,872,385. First, a non-reactive frequency of a crystal unit A is determined, a radio-frequency current is supplied to the series circuit A+ B composed of said crystal unit A and a circuit B which is adjustable to non-reactiveness, and the circuit B is adjusted so that the phase of the terminal voltage across said series circuit A+B coincides with the phase of the terminal voltage across the circuit B. Next, said crystal unit A is replaced by an element A, whose construction is similar to the said circuit B, and is adjustable to non-reactiveness, and the element A is adjusted so that the phase of the terminal voltage across said series circuit A+B coincides with the phase of the terminal voltage across the circuit B. Lastly, the construction of A is fixed, whereby said element A is always available as a substitute for A, for checking the non-reactiveness of the circuit B.