The semiconductor photo-sensitive diode structures with palladium contact (Schottky diodes, heterojunctions) can be used as a sensors of the hydrogen and hydrogen-containing gases. It was found that integral photo-sensitivity of such structures changed in atmosphere of the hydrogen. In Pd-n-InP photodiode structures the variation of the photo-emf at H₂ in the air 0,3 pm reach 1,5—2,0 orders of the magnitude. In Pd-SiO2-InGaAs-n-InP photodiode structures the variation of photo-emf in gaseous mix with 5 % H₂ in spectral interval 1,30—1,55 mm reach more order of the magnitude. In hybrid structure Pd-p-InP-p-InGaAs the change of photo-emf in gaseous mix with 0,05 % H₂ at l = 0,9 mm makes up factor 7—10. The mechanism action of hydrogen on photo-emf is determined mainly of variation Shottky barrier and also sometimes of changing transparency coefficient of photocarriers.