We propose a generalized wave function based on the flexible original THSR (Tohsaki, Horiuchi, Schuck, Röpke) wave function [ A. Tohsaki et al. Phys. Rev. Lett. 87 192501 (2001)], which is applicable to studies of general cluster structures in nuclei. The ground-state band in 20Ne is investigated by using this generalized wave function and the energies obtained agree well with the experimental values. Moreover, it is found that the single generalized THSR wave functions almost completely coincide with the exact solutions of the α+16O resonating group method for the ground-state band in 20Ne. For the ground state, for instance, the squared overlap between them is 99.3%. This indicates that the THSR model can also be extended to study more compact cluster states in nuclei such as, e.g., the ground-state band in 20Ne.