We propose a new improved model-independent method for calculating the pion charge radius.
In a recently-proposed model-independent method for the pion charge radius,
we find it difficult to compute the pion charge radius for small pole mass $M_{\rm{pole}}^2$ and volume
due to systematic errors coming from finite volume effect and higher-order contamination of the Taylor expansion of the form factor.
We circumvent this difficulty by introducing a new appropriate function and
propose a modified method that can calculate the pion charge radius with less systematic errors
in the small $M_{\rm{pole}}^2$ and volume cases.
As preliminary results, we check that our improved model-independent method works well
on a mockup data and also an actual lattice QCD data at the pion mass of 0.51 GeV.