The present invention relates to a magnetic stimulation method and a personalized cognitive training method performed alternately, and a device and a system therefor. The magnetic stimulation system according to an embodiment of the present invention comprises: a control unit determining a magnetic field output in accordance with user data comprising a motor threshold and the brain region being stimulated; and a power module connected to a coil generating magnetic field, and supplying power such that the coil generates the determined magnetic field. The control unit can comprise: a motor threshold measurement module measuring the motor threshold of a user by means of a magnetic field changing module; and the magnetic field changing module, using an MRI image of the user, controlling the magnetic field output by adjusting magnetic field-related parameters determined in accordance with the distance to the brain region being stimulated, the state of the user's brain comprising at least one of the brain shape, brain size and head shape of the user, and the measured motor threshold.