This invention provides a nucleic acid amplification device whereby the abundance of a target molecule can be maintained before and after a step of separately amplifying a sample such that highly accurate analysis results that can be applied to gene expression analysis can be obtained. Also, a nucleic acid amplification device having a structure in which a plurality of minute reaction cells each comprising a set of a bead-retaining space capable of retaining a single analysis bead and a reagent reaction space retaining no bead but having a volume that is large enough to cause a reagent reaction therein are positioned so as to form a planar face is provided.