Brevetoxin B (1), a potent neurotoxin, was isolated from the red tide organism Gymnodinium breve Davis in 1981. The unique structural features and biological activity of this molecule have attracted the attention of synthetic chemists. We have already reported the efficient method for the convergent synthesis of polycyclic ethers via the intramolecular allylation and subsequent ring-closing metathesis. Herein we report the convergent total synthesis of 1 based on our own methodology. The reaction of the bicyclic compound 9, prepared from the known compound 6, with the allylic silane 10 in the presence of TMSOTf gave the desired product 11, stereoselectively. The JK ring segment 3 was synthesized in 11 steps including one-carbon elongation from 11. Palladium-catalyzed coupling of the ketene acetal triflate 15 and the organozinc reagent 16 gave the enol ether 17, which was converted to the diene 22. The construction of the A ring via ring-closing metathesis afforded the ABC ring segment 4. The chlorosulfide 4 was treated with the alcohol 5 in the presence of AgOTf and DTBMP to give the O,S-acetal 24. Intramolecular allylation of 26 using AgOTf as a Lewis acid provided the desired product 27, stereoselectively. Chemoselective reduction of the olefinic moiety in the E ring of 29 was carried out under the condition of the diimide reduction to afford 30. The heptacyclic compound 30 was converted to the alcohol 2 in 6 steps including one-carbon elongation. The alcohol 2 and the carboxylic acid 3 were connected successfully by Yamaguchi conditions to give the ester 33. The construction of the polycyclic framework of 1 was performed via the intramolecular allylation and subsequent ring-closing metathesis to yield 38. After the TBS and TBDPS protecting groups were removed using HF・pyr, chemoselective oxidation of the allylic moiety with MnO_2 furnished brevetoxin B (1). The synthetic brevetoxin B exhibited spectroscopic data identical with those of natural brevetoxin B.