  It is known that, in a pure one-dimensional case, Charge-Density-Wave (CDW)
phase is destroyed by a magnetic field, whereas Spin-Density-Wave (SDW) one
does not feel the field. In reality, SDW phase is often observed in
quasi-one-dimensional (Q1D) conductors due to the so-called "nesting" property
of their electron spectra. We show that, in the latter case, a high magnetic
field generates some "anti-nesting" term in a Q1D electron spectrum, which
destroys SDW phase. We suggest to perform the corresponding experiments in SDW
phases of the real Q1D organic conductors with chemical formula (TMTSF)$_2$X
(X=PF$_6$, ClO$_4$, etc.).
