To surely control flow of fluid by simple constitution and manufacture a valve at a low price.

A first insulating body 29 and a second insulating body are interposed inside a primary coil 27 inserted into the interior of a casing 26. A plurality of first spaces 31 communicated to the inflow passage of an inlet casing are defined between the first insulating body 29 and the second insulating body 30. A second insulating body 30 is provided with first flow passages 32 respectively penetrating through the positions corresponding to the respective first spaces in the radial direction. A valve body 33 inserted into the inner space of the second insulating body 30 is formed with a cutout part 33a. The valve body 33 usually closes a first flow passages 32, but when primary current is let flow in the primary coil 27, it is contracted in the direction of the inner diameter so as to open the first flow passages 32. The valve body 33 is provided with a plurality of second flow passages 34 pentrating through in the radial direction. A second space 35 defined inside the valve body 33 is communicated to the outflow passage of an outlet casing.