Abstract: The whole DNA sequence coding for flagellin of E. coli (hag gene) cloned in phage .lambda. was determined. The hag gene is introduced into pBR322 and the region of the hag gene concerning the antigencity of flagella is lacked, into which linkers are inserted. Where the vector in which foreign DNA is inserted in the linker is introduced in E. coli forming no flagella, the E. coli can form flagella and possesses motility. The flagella comprises flagellin fused with foreign peptide encoded by the foreign DNA. Namely, the foreign peptide is excreted outside of bacteria. This system can be utilized in determination of epitope and preparation of antigen as well as excretion of peptide.