A nucleic acid detection system according to an embodiment is a nucleic acid detection system to detect a target nucleic acid in a sample and includes a thermal inactivation chamber, an amplification chamber, and a detection chamber, all of which constitute a liquid flow path. In this system, liquid flows through the thermal inactivation chamber, the amplification chamber, and the detection chamber sequentially. The thermal inactivation chamber includes a reagent to thermally inactivate and decompose the sample. The amplification chamber includes a reagent to amplify the target nucleic acid. The detection chamber includes a test strip to conduct a Cas enzyme reaction with the target nucleic acid and a lateral flow detection.