PURPOSE: To produce easily a tube mold of a small size for continuous casting by covering a metallic case for the mold on a refractory core having the same outside shape as the inside surface shape of the mold, evacuating the spacing between said case and core and subjecting the same to hot isotropic pressurization.

CONSTITUTION: A core 1 having the same shape as the internal space shape of a tube mold for continuous casting is manufactured from refractories such as alumina. A case 2 made of a metallic material to be made into the tube mold, that is, a metallic material having Cu or a Cu alloy on the outside and Ni or an Ni alloy layer on the inside is put on the outside of such core 1. A slight spacing is provided inbetween by winding a wire rod or belt-like material on the outside of the core 1, and is evacuated to a vacuum after the contact parts of the core 1 and the case 2 are hermetically sealed by means of an adhesive agent 3. Both are subjected to a hot isotropic pressurization treatment using a gaseous substance at high temp. and high pressure to adhere tightly the case 2 to the core 1, whereafter the core is removed and the tube mold for continuous casting is manufactured.