A Walkman brand cell phone enabling users to download music onto their handsets will go on sale in the Japanese market next month in a joint project between KDDI and Sony, KDDI Corp. announced Monday.

KDDI Corp., Japan's second-largest mobile phone company, scheduled a news conference Monday morning to announce details. Officials from Sony Ericsson Mobile Communications AB also were to attend the conference, Sony Corp. (SNE) spokeswoman Saori Takahashi said.

The new product, Japan's first Walkman brand cell phone, will include flash memory to store about 500 songs, using energy-saving technology developed by Sony Ericsson, according to Japan's largest financial daily, the Nihon Keizai Shimbun.

It will enable users to play music continuously three times as long as current KDDI models, or if used only as a music player, the handset could operate for about 30 hours on a single charge, the newspaper said.

Users will be able to download songs via the Internet or record off other media such as CDs via personal computer. The phones will be sold under both KDDI's au and Sony's Walkman brands, according to the report.

The retail price was expected to be about 20,000 yen, or about $179, it said.

Sony has been selling Walkman brand cell phones in markets such as Europe through Sony Ericsson, a 50-50 joint venture between Sony and Ericsson AB (ERICY), since last summer, the report said.

By teaming up with KDDI in the Japanese market, it hopes to increase sales there, where service providers market handsets, it said.

Sony Ericsson supplies handsets to all service providers in Japan and could offer the Walkman version to other firms besides KDDI, it said.