This invention relates to methods for amplifying target nucleic acid. A target nucleic acid is contacted with specific primers in the presence of DNA polymerase and deoxyribonucleotide triphosphates to produce an amplification solution with a volume of 5 pl or less. The amplification solution is subjected to a denaturation temperature of 75 C.-85 C. for 1.5 second or less; and then to a polymerisation temperature of 25 C.-45 C. for 1 second or less. These denaturation and polymerisation steps are repeated to amplify the target nucleic acid. Devices and systems for performing such methods are also provided.

A flow path plate for thermal cycle includes a plate-shaped member extending in a horizontal direction, a heating flow path extending in a horizontal direction in the plate-shaped member, a cooling flow path extending in a horizontal direction in the plate-shaped member, a connecting flow path connecting the heating flow path and the cooling flow path, a heating-target surface contacted by a first temperature adjuster configured to heat the heating flow path, and a cooling-target surface contacted by a second temperature adjuster configured to cool the cooling flow path at a temperature lower than that by the first temperature adjuster. A target sample is conveyed from the heating flow path to the cooling flow path, the heating-target surface is situated under the heating flow path, and the cooling-target surface is situated above the cooling flow path.