  From recent analysis of the $\pi\pi$ scattering amplitude, it has been
claimed that there exists a broad and light $\sigma$ meson. However, if this
meson really exists, it must also appear in other observables such as the pion
scalar form factor. With the use of unitarity and dispersion relations together
with chiral perturbation theory, this form factor is analyzed in the complex
energy plane. The result agrees well with the empirical information in the
elastic region and reveals a resonance pole at $\sqrt{s}=445-i235$ MeV. This
gives further strong evidence for the existence of the $\sigma$ meson.
