The invention relates to a portable apparatus for generating a magnetic field intended to induce a low-frequency sinusoidal electric current in a region of the human body to which it is applied, comprising four angular magnet sectors (6-1 to 6-4) which are inscribed within the same circle (C), are centred on the same rotation axis (X-X) and spaced angularly from one another, the polarity of two adjacent magnet sectors being opposed, and means for rotating the magnet sectors at a predetermined speed about the rotation axis in such a way as to generate an induced sinusoidal current at a predefined frequency, each magnet sector comprising the same geometric shape with an internal angular opening (α) of between 85 and 90°, an external angular opening (β) of between 20° and 0°, and two lateral edges (8-1 to 8-4) defining a radius extending by a distance (d) which is between one third and two thirds of a distance (D/2) separating the rotation axis from the free end of the magnet sectors.
