A microchannel chip system and a detection chip capable of improving detection precision are provided. The detection chip 1 of the microchannel chip system comprises a carrier retention section 13 capable of retaining a carrier supporting a second chemical substance which generates a signal by reacting with a first chemical substance and a microchannel flow channel 10 provided with a supply flow channel 14 which supplies a liquid material containing the first chemical substance to the carrier retention section 13. A carrier mobilization means (a protrusion 2) is provided for enhancing of the reactivity of the second chemical substance supported in the carrier 9 with the first chemical substance contained in the liquid material by moving the carrier retained in the detection chip 1.