The rare decay B0→γγ is searched for in 104fb-1 of data, corresponding to 111×106BB̄ pairs, collected with the Belle detector at the KEKB asymmetric-energy e+e- collider. No evidence for the signal is found, and an upper limit of 6.2×10-7 at 90% confidence level is set for the corresponding branching fraction. © 2006 The American Physical Society.