We investigate the unpolarized virtual photon structure functions F γ 2 (x, Q 2 , P 2 ) and F γ L (x, Q 2 , P 2 ) in perturbative QCD for the kinematical region Λ 2 ≪ P 2 ≪ Q 2 , where −Q 2 (−P 2 ) is the mass squared of the probe (target) photon and Λ is the QCD scale parameter. Using the framework of the operator product expansion supplemented by the renormalization group method, we derive the definite predictions for the moments of F γ 2 (x, Q 2 , P 2 ) up to the next-to-next-to-leading order (NNLO) (the order αα s ) and for the moments of F γ L (x, Q 2 , P 2 ) up to the next-to-leading order (NLO) (the order αα s ). The NNLO corrections to the sum rule of F γ 2 (x, Q 2 , P 2 ) are negative and found to be 7% ∼ 10% of the sum of the LO and NLO contributions, when P 2 = 1GeV 2 and Q 2 = 30 ∼ 100GeV 2 or P 2 = 3GeV 2 and Q 2 = 100GeV 2 , and the number of active quark flavors n f is three or four. The NLO corrections to F γ L are also negative. The moments are inverted numerically to obtain the predictions for F γ 2 (x, Q 2 , P 2 ) and F γ L (x, Q 2 , P 2 ) as functions of x.