The 90" differential cross section of the 12C(3He,y,,)1S0 reaction has been measured at 'He-particle energies from 5.24 to 13.95 MeV in steps varying from 100 to 300 keV. They rays have been detected by a 23 cm long x 23 cm diameter NaI(T1) crystal spectrometer enclosed in an anticoincidence shield. The yield curve shows a resonant structure at the energies E,,, = 17.04 -+ 0.06, 18.65 -+ 0.06, 19.55 -+ 0.08,20.40-+ 0.07, and 21.61 5 0.07 MeV. La section efficace differentielle de la reaction 12C(3He,y,)1S0 a ete rnesurke pour des energies des particules-'He allant de 5.24 i 13.95 MeV. Les rayons gamma ont e t i detectes par un crystal de NaI(T1) entoure d'un scintallateur plastique en anticoincidence. La courbe d'excitation montre de la structure aux energies E,,, = 17.04 -+ 0.06, 18.65 ? 0.06, 19.55 5 0.08, 20.40 2 0.07 et 21.61 t 0.07 MeV.