Fluctuation properties of the fundamental light beam in intracavity second harmonic generation (ISHG) are studied theoretically. It is shown that the field produced by the ISHG can be described as a superposition of a coherent component and bivariate Gaussian noise field. Using this property of the ISHG field a generating function for photon counting statistics is obtained. From this generating function various expressions for quantities characterizing statistical properties such as photon counting distribution, factorial moments, and statistics of times are calculated. Curves are presented to illustrate the behavior. These results for the ISHG are also compared with those obtained for the optical parametric oscillators.