  We present a measurement of the unitarity triangle angle phi_3 using a Dalitz
plot analysis of the three-body decay of the neutral D meson from the B+- -> D
K*+- process. Using a 253 fb-1 data sample collected by the Belle experiment,
we obtain 56 signal candidates for B+- -> D K*+-, where the neutral D meson
decays into K_S pi+ pi-. From a maximum likelihood fit we obtain
phi_3=112+-35(stat)+-9(syst)+-11(model)+-8(nonresonant B -> D K_S pi).
