The present invention provides a flow-channel device for detecting light emission, which suppresses a noise originating in unnecessary light emission, and can be simply bonded with the use of an organic material. The flow-channel device having a flow channel is structured by the bonding of at least two substrates, wherein at least any one substrate has a first groove which constitutes the flow channel, and a second groove for arranging an adhesive therein which contains an organic material, and a light-shielding layer is provided on an inner wall of the second groove so as to block a light emitted from the second groove from penetrating into the first groove.