A bulk magnetoresistance effect material of a composition represented by the general formula: T.sub.100-A M.sub.A (wherein T is at least one element selected between Cu and Au; M is at least one element selected from the group consisting of Co, Fe, and Ni; and A is in the range: 1.ltoreq.A.ltoreq.50 by atomic percent) is prepared by casting a molten mixture of the above composition, and subjecting the resulting casting to homogenization and further to heat treatment. The bulk magnetoresistance effect material is high in the rate of change in the electrical resistance thereof, i.e., shows a large magnetoresistive effect and can be obtained in such bulk form in arbitrary shapes adaptable for various uses. Using the material, various types of magnetoresistive elements are obtained.