Abstract: A magnetic belt for medical purposes, which exposes the lumbar portion of a human body with magnetic flux has been found. The magnetic belt comprises an elastic belt body, a flexible sheet removably and slidably mounted on the belt body, and a plurality of permanent magnets removably mounted in said sheet. The belt body is made of elastic cloth and the coefficients of elasticity differs breadthwise. The sheet is made of flexible plastic, such as ABS (Acryl-Butadiene-Styrene), having a plurality of circular holes for accepting the permanent magnets. Each permanent magnet is mounted in a plastic housing or a capsule having a flange which engages with the edge of the hole of said sheet. The permanent magnet is, for instance, an alloy of samarium and cobalt with a surface magnetic flux of approximate 1,200 gauss. The present magnetic belt is, when attached on the lumbar portion, effective for reducing stiffness or pain in the muscles of the human body.