Sony is willing to pay about 50 billion yen ($600 million) for the plant in Nagasaki, which it sold to Toshiba in 2008 for about 90 billion yen, the Nikkei daily said.
The plant makes chips for Sony's PlayStation3 game console, Toshiba television sets and other digital products but the firm wants to sell up as they have too few other applications, Kyodo News and national network NHK said.
Sony will use the factory to double its output of metal-oxide semiconductor sensors (SMOS) to the equivalent about 40,000 a month, the Nikkei said.
"By boosting output of the chips and lowering production costs, (Sony) aims to catch up with such firms as South Korea's Samsung Electronics Co. and US players," the Nikkei said.
The global market for SMOS is estimated to be worth $4.2 billion in 2010, and expected to nearly double by 2014, the Nikkei said.
Sony said in a statement that the media reports were not an official release from the company and declined to make further comment.