Disclosed is a nucleic acid amplification method which is based on a new principle and enables to amplify a nucleic acid having a specific nucleotide sequence in a simple manner, within a short time and with efficiency. The nucleic acid amplification method comprises the steps of: (a) conducting a DNA polymerase chain reaction by using, as a template, DNA comprising a nucleotide sequence to be amplified and using a primer pair having a nucleotide sequence complementary to the nucleotide sequence to be amplified, thereby producing a linear DNA fragment; and (b) conducting a chain-substituting DNA polymerase chain reaction in a chaining manner by using cyclic single-stranded DNA comprising the same nucleotide sequence as that of at least one of the primer pair as a template and employing the 3′-terminus of the linear DNA fragment produced in step (a) as the replication origin.