Nucleon form factors from lattice QCD near the physical point

We present results of the nucleon form factors measured on a large-volume lattice (8.1 fm)⁴ at almost the physical point in 2+1 flavor QCD. The configurations are generated with the stout-smeared O(a) improved Wilson quark action and Iwasaki gauge action at beta=1.82, which corresponds to the lattice spacing of 0.085 fm. The pion mass at the simulation point is about 145 MeV. A large spatial volume of (8.1 fm)³ allows us to investigate the form factors at small momentum transfer region. In this talk, we focus on the iso-vector form factors of the nucleon. We carefully examine both electric (G_E) and magnetic (G_M) iso-vector form factor shapes with a model-independent analysis based on the z-expansion method in order to determine the electric root-mean squared radius and magnetic moment.