To provide a pressure variable valve device being hardly disordered in the control of pressure by the external disturbance.

This pressure variable valve device 2 has at least one double- pole stepping motor element 50 and 60 having the characteristic to be easily in one direction, a worm 40 connected to double-pole rotors 51 and 61 of the double-pole stepping motor element, a worm wheel 32 engaged with the worm, and a rotational pressing mechanism 31 connected to the worm wheel and capable of adjusting the pressure force to a valve element 24 corresponding to the rotation of the worm wheel. Typically, a pair of double-pole stepping motor elements are substantially extended in parallel with each other, and rotors are respectively connected to the worm in such manner that the worm is rotated in one rotating direction G1 by the magnetic field applied to a stator 52 of one of the stepping motor element 50 in one direction, and further rotated in the same rotating direction G1 by the magnetic field applied to a stator 62 of the other stepping motor element 60 in the other direction.