The form factor for the excitation of the 3.56 MeV level in Li6 by electron scattering is calculated with an oscillator cluster model. The transition to the 3.56 MeV level occurs with spin- and isospin-flip of the cluster in Li6 through the transverse component, while to the 2.18 MeV level changes the relative motion between cluster mainly through the longitudinal component of the electromagnetic interaction. The cluster model, when combined with the previous result obtained by Kudeyarov et al., can systematically reproduce all the experimental form factors for these inelastic electron scatterings and elastic scattering. From resulting parameters of the wave function for the 3.56 MeV level, it is concluded that the α and singlet deuteron clusters at this level are rather isolated in just the same way as the α and triplet deuteron clusters in the ground state.