The paper presents data on the production of the He-3 nuclide in rocks under the effect of cosmicray particles. The origin of the nuclide in the ground in neutronand proton-induced spallation reactions, reactions induced by high-energy muons, and negative muon capture reactions is analyzed. The cross sections of reactions producing He-3 and H-3 are calculated by means of numerical simulations with the GEANT4 simulation toolkit. The production rate of the He-3 nuclide in the ground is evaluated for the average level of solar activity at high geomagnetic latitudes and at sea level. It is proved that the production of He-3 in nearsurface ground layers by spallation reactions induced by cosmic-ray protons may be approximately 20% of the total production rate of cosmogenic He-3. At depths of 10-50 m.w.e., the accumulation of He-3 is significantly contributed by reactions induced by cosmic-ray muons. Data presented in the paper make it possible to calculate the accumulation rate of He-3 in a rock depending on depth that is necessary for the evaluation of the exposure time of the magmatic or metamorphic complex on the Earth's surface (He-3 dating).