The invention provides an electromagnet which comprises a shell (5), a framework (6), a front yoke sleeve (8), a back yoke sleeve (10) and a magnetic core (11), wherein the shell is fixedly connected with the front yoke sleeve (8); a coil (4) is wound in a die cavity of the framework (6); the back yoke sleeve (10) is installed in an inner hole in the framework (6); the magnetic core (11) is provided with a plurality of guide grooves (111) distributed around the magnetic core (11); ball bodies (12) are installed in the guide grooves (111); and the magnetic core moves relative to the back yoke sleeve (10) through the ball bodies (12). The ball bodies form the bearing points for the motion of the magnetic core, the magnetic core does not directly contact the back yoke sleeve or guide sleeves, and rolling friction is formed due to the contact of the ball bodies, thereby lowering the motion resistance of the magnetic core, enhancing the motion sensitivity and motion stability of the magnetic core, and effectively enhancing the response speed and control stability of the electromagnet.