Cavitation test has been carried out for flat plate helical inducer with various blade angles. Effects of inducer blade angles on head characteristics and cavitation induced oscillation phenomena are described in the present paper. Head characteristics, head breakdown point due to cavitation and the range of cavitation induced oscillation occurring are correlated as guiding principles for inducer design. Then measured casing wall pressure distributions and observed cavitation behaviors are discussed from the aspect of advance detection of cavitation surge oscillation.