Electron transfer reactions have been studied as the time development of many-electron wave functions based on the time-dependent variational principle (TDVP). The equation of motion (EOM) of the pseudoclassical mechanics, which is described with canonical coordinates, has been derived by introducing a new trial wave function of the TDVP in the polar form. Based on the EOM, it has been shown that the transition state of the electron transfer corresponds to the saddle point at which an unstable broken-symmetry wave function occurs in the variational method for stationary states. By the maximal decoupling condition, canonical collective coordinates of the electron transfer have been separated in the TDVP-EOM with canonical variables. A simple example has been given for a symmetric electron transfer reaction in H-3 by using the time-dependent cluster expansion of wave function.