  We report on a high statistics measurement of the cross section of the
process gamma gamma to pi^+ pi^- in the center-of-mass energy range 0.8 GeV/c^2
< W < 1.5 GeV/c^2 with 85.9 fb^-1 of data collected at sqrt(s)=10.58 GeV and
10.52 GeV with the Belle detector. A clear signal for the f_0 lr 980 resonance
is observed. From a fit to the mass spectrum, the resonance's mass, pi^+ pi^-
and two-photon decay widths are found to be 985.6^+1.2
_-1.5(stat)^+1.1_-1.6(syst) MeV/c^2, 34.2^+13.9_-11.8(stat)^+8.8_-2.5(syst)
MeV, and 205^+95_-83(stat)^+147_-117(syst) eV, respectively.

High Energy Physics - Experiment