In a composite material consisting of a piezoelectric and a piezomagnetic phase which are mechanically coherent, electric and magnetic fields are converted into each other by a two-step process involving mechanical deformation as the intermediate step. We have developed such a material on the basis of a Co ferrite-Ba titanate eutectic which is unidirectionally solidified so as to obtain an aligned two-phase structure. The maximum value of the magneto-electric effect obtained at present is 0.13 V/cm Oe at room temperature. The dimensionless quantity 4π(dP/dH) is 0.2 or a factor of 200 higher than the best single-crystal material known at room temperature (Cr2O3).