In this study, we have investigated the photocatalytic properties for pyrochlore-type oxides Sn₂M₂O₇ (M = Nb and Ta) and their solid solutions. Although the volume of evolved H₂ is very low, Pt-loaded Sn₂Nb₂O₇ and Sn₂Ta₂O₇ showed photocatalytic activity for H₂ evolution from water under blue LEDs irradiation. The absorption edge of the Sn₂Nb_xTa_2−xO₇ solid solutions was in a position between those of Sn₂Nb₂O₇ and Sn₂Ta₂O₇, and the band gap became narrow monotonically as the value of x increased. Although some variability was observed, there was not the clear dependence on the composition value of x.