A radial multi-block copolymer contains a tapered block as represented by the following formula 1. The radial multi-block copolymer, which includes a polystyrene block, a poly(isoprene-styrene)tapered block, a polyisoprene block, and a polybutadiene block, can be used as an excellent pressure-sensitive adhesive material. (pA-pT-pB)m-X-n(pC-pB-pT-pA)  Formula 1 where pA is the polyvinyl aromatic block; pT is the poly(isoprene-styrene)tapered block; pB is the polyisoprene block; pC is the polybutadiene block; X is the residue of a multi-functional coupling agent used in preparation of the radial multi-block copolymer; m and n are integers equal to or greater than 1, representing the number of branches associated with X; and pT=pTA+pTB, where pTA is the pA component of pT, and pTB is the pB component of pT.