There is provided a base sequence analysis method including: a nucleic acid amplification procedure of obtaining an amplification product by a nucleic acid amplification reaction, a turbidity measurement procedure of measuring turbidity of a reaction solution of the nucleic acid amplification reaction; and a melting curve analysis procedure of performing melting curve analysis of a probe nucleic acid chain and the amplification product at a reaction site of the nucleic acid amplification reaction. This base sequence analysis method makes it possible to consecutively perform a nucleic acid amplification reaction and melting curve analysis at the same reaction site.