Cross sections of the reaction 63Cu(p, 3n)61Zn (T12 = 1.48 min) have been measured for proton energies from 30 to 47 MeV with an isotope separator on-line (ISOL) attached to a cyclotron. The method of the cross section measurement with the ISOL system has been developed. The cross sections obtained by the ISOL method agreed with those by the stacked foil method. In addition, cross sections of the 63Cu(p, p3n)60Cu (T12 = 24 min) reaction have been measured by the stacked foil method at proton energies up to 52 MeV.