Penning ionization of HCl upon collision with metastable He*(2(3)S) atoms was studied by two-dimensional (collision-energy/electron energy resolved) Penning ionization electron spectroscopy and by classical trajectory calculations. Collision energy resolved studies enable us to obtain important information about stereo dynamical aspects on this reaction; sideways approaches of the He* atoms on H-Cl molecular axis play a dominant role in the ionization event for producing HCl+(X (2)Pi(i), v' = 0, 1), and glancing collision is one of the dominant trajectories of the He* atoms to produce HCl+(A, (2)Sigma(+)). It was also found that the formation of vibrationally excited HCl+(X (2)Pi(i), v' > 1) through the unidentified HCl** Rydberg state was influenced by a strong attractive interaction, whereas the formation of the HCl** Rydberg state, dissociating to H(1s) and autoionizing Cl**(D-1(2) nl) atoms, was found to be affected by a repulsive interaction around the Cl end of the HCl molecule.