An electromagnetic actuator includes a stator unit having N poles having the width LP, and at least one coil surrounding one of the poles, wherein N≦3, and a magnetic portion, which is movable, relative to the stator unit, in a direction of relative movement and over a course of travel C, and including N+1 magnetized areas, the magnetizations of which are perpendicular to the relative movement direction and in alternate directions. The magnetic portion includes a yoke for closing off the magnetic fluxes passing through the magnetized areas, the course of travel C of the magnetic portion being less than or equal to the width LP of each pole, and the thickness of the magnetized areas perpendicular to the direction of movement being less than the course of travel C of the magnetic portion.