An amorphous IV-VI diluted magnetic semiconductor Ge_0.7Mn_0.3Te film has been prepared by the RF sputtering on a glass substrate at room temperature. Fine crystalline wires could be sucessfully formed in the amorphous matrix by scanning a focused laser beam irradiation. The uniform crystalline pattern has been obtained with a low laser power. It was clarified that the crystalline phase in the amorphous matrix is ferromagnetic. The magnetic transport properties of crystalline wires prepared by phase transformation have been also investigated and compared with those of crystalline wires prepared by the photoetching process. The different magnetoresistance behaviors were observed when the magnetic field was applied along the transverse direction of these wires.