PURPOSE: To obtain an I-shaped plunger solenoid having a movable iron core with a high return stability thereby to make it possible to raise the response reliability of an electromagnetic valve, by forming subdividing grooves in a magnetically attracting surface of each of the movable and fixed iron cores.

CONSTITUTION: A movable iron core 5 magnetically attracted to a fixed iron core 1 by excitation of an electromagnetic coil in opening the valve through an attracting surface subdividing groove 8 formed in an attracting surface 6 of the movable iron core 5 and an attracting surface subdividing groove 4 formed in an attracting surface 2 of the fixed iron core 1. While having an attracting relationship through divided attracting surfaces each having a small area defined by spider's web-shaped attracting surface subdividing grooves, both the attracting surfaces are in a pressurized state since air flows into annular grooves 7 and radial grooves 3 of the subdividing grooves 8, 4, respectively. Therefore, the synergistic effect of the attracting relationship therebetween and the pressurized state overcomes the fluid pressure resulting from generation of a seal region, thereby allowing a high return stability of the movable iron core when the electromagnetic coil is deenergized to close the valve. Accordingly, it is possible to largely improve the response reliability in the valve function.