PURPOSE: To control a flow rate or a pressure with high precision and expand a flow rate control range by preventing a movable iron core from coming in slidable contact with a coil, a stator core and the like.

CONSTITUTION: When a coil 12 has been energized with an electric current, there appears an electromagnetic attraction pulling a movable iron core 17 toward a direction opposite to a valve seat 9. Consequently, a gap corresponding to the magnitude of the coil current is formed between a valve body 26 and the valve seat 9. The movable iron core 17 is supported with movable iron core support means 14 and 16 comprising a plate spring, and hard to move in the radial direction of the coil 12, thereby enabling preventing the movable iron core 17 from coming in slidable contact with a stator core 11 and the coil 12 or a cylindrical member and the like fitted to the internal surface thereof. Consequently, a flow rate and a pressure can be controlled with high precision.