The LEPS experiment at SPring-8 has collected data in reactions of 1.5-2.4 GeV photons with a liquid deuterium target. The pentaquark baryon Θ+ was searched for in a missing mass spectrum of K- and proton from a deuteron. A peak structure of 4-5σ was observed at 1.53 GeV/c2 above background spectra which were estimated by two complementary methods. Further data is being collected with a higher intensity beam. Confirmations and systematic studies of the Θ+ will continue at new facilities of SPring-8 and J-PARC.