To provide a technique for easily obtaining silica microparticles at low cost based on the biomineralization of Bacillariophyta(diatom).

A method for producing the silica microparticles is provided, comprising the step of culturing, using a silisic acid-containing medium, Eschelichia coli transformed with an expression vector containing the base sequence mentioned below(Sequence No.1) as a gene encoding a peptide to be expressed and the sequence complementary thereto. Preferably, the silicic acid-containing medium to be used is prepared by adding tetramethoxysilane and dilute hydrochloric acid, or by using water with diatom alive therein. The base sequence(Sequence No.1) is ATG AGC AGC AAA AAA AGC GGC AGC TAT TCT GGC TCT AAA GGT AGT AAA CGT CGC ATT TTG TAA.