GAS DETECTION ELEMENT AND GAS DETECTOR

PROBLEM TO BE SOLVED: To prevent gas from being unintendedly supplied to the surface of a color development layer, in a detection element equipped with a base material, constituting a light waveguide and the color development layer developing a color by reaction with a target substance.SOLUTION: The gas detecting element (30) is equipped with a first holding member (21), a second holding member (22) and a closure member (26), in addition to the base material (31) and the color development layer (32). A first holding member (21) is formed into a frame shape and laminated on the base material (31) so that the color development layer (32) so as to face the opening of the first holding member (21). A second holding member (22) is laminated on the base material (31) on the side opposite to the first holding member (21), to hold the base material (31) along with the first holding member (21). The closure member (26) is laminated on the first holding member (21), on the side opposite to the base material (31) so as to close the opening of the first holding member (21) and has an inflow passage (26a) for allowing a gas to flow into the gas chamber (20), surrounded by the first holding member, and an outflow passage (26b) for allowing the gas to flow out of the gas chamber (20) formed thereto.