Akitoshi Kojima, chairman of home electronics chain Kojima Co., has been effectively ousted by other board members after he opposed the planned acquisition of his firm by its bigger rival, Bic Camera Inc., according to sources.

Kojima said Monday that the chairman will resign and become an adviser. The move is to be formalized at a shareholders' meeting June 28.

The announcement came after the chairman, the first son of the company's late founder, Katsuhei Kojima, expressed opposition to the acquisition of Kojima by Bic Camera, which was decided by the Kojima board May 11.

President Etsuo Terasaki said Kojima has a different vision for the mass retailer than other board members.

Bic Camera, ranked fifth in the industry, has nearly 40 stores in urban areas, while sixth-ranked Kojima has about 200 stores mainly in suburban areas.