Photo-induced living cationic polymerization of isobutyl vinyl ether (IBVE) has been newly developed in the presence of diphenyliodonium iodide (DPII). Zinc iodide was used as an activator in the polymerization reaction. A linear relationship between ％ monomer conversion and the number average molecular weight of the resulting polymer reveals the living nature. The increase in both the polymer yield and its molecular weight until the original monomer was exhausted reveals that the propagating cationic species have the long lifetime due to the absence of termination or chain transfer process. It became also evident that a PIBVE-based block copolymer can be obtained by the subsequent monomer addition technique from this photo-induced system. The effects of various factors such as concentrations of DPII and zinc iodide, temperature, and duration of photo-irradiation were also discussed.