A systematic study of the decay rates of antiprotonic helium ((p) over bar He-4(+) and (p) over bar He-3(+)) at CERN Antiproton Decelerator has been made by a laser spectroscopic method. The decay rates of some of its short-lived states, namely those for which the Auger rates gamma(A) are much larger than their radiative decay rates (gamma(rad)similar to1 mus(-1)), were determined from the time distributions of the antiproton annihilation signals induced by laser beams, and the widths of the atomic resonance lines. The magnitude of the decay rates, especially their relation with the transition multipolarity, is discussed and compared with theoretical calculations.