PURPOSE: To continuously mold a continuous sealing material having elasticity easily and at a low cost by applying a foaming sponge in a tube while the tube is extrusion molded.

CONSTITUTION: While an elastic resin material tube 3 such as ethylene-vinyl acetate or the like is extrusion molded, a foaming sponge-shaped continuous material 2 is incorporated successively to mold a continuous material continuously. As a rubber material is not used as in the conventional process, a vulcanizing molding process is eliminated and a continuous sealing material 1 may be prepared by a continuous molding very simply and at low cost.