Abstract: This invention provides a strong magnetism therapeutic apparatus with permanent-magnet sets rotating at low frequency in which a base set made of magnetic material is fixed on a plate capable of rotating in both direction and at least two adjacent permanent-magnet sets for producing strong magnetic field are secured to said base set and separated by a isolating block made of non-magnetic material. A pole head is secured to the upper surface of each permanent-magnet set. The penetrating depth within the object to be treated is up to 500 mm. When used as a therapeutic instrument, this apparatus can produce desirable analgesic effect for late patient of, for example, cancer without the minus effect of radiation therapy and chemotherapy. The apparatus has also wide application in biologic and chemical field.