The deal, with management and technology consultancy BearingPoint, will see 1,000 of the phones put into the hands of the company's analysts and workers across the country, the two companies said on Monday.
BearingPoint said it is adopting the iPhone with the aim of improving the productivity of its consultants and helping them access information more easily. Right now the consultants carry both a cellular telephone and a data modem card for a PC.
The deal is potentially significant for the iPhone in Japan.
Unlike other nations the use of smartphones in the Japan market is still low. A proprietary second-generation cellular technology left companies like Blackberry out of the market and Japanese carriers, all of which determine the specifications of handsets they sell, were slow off the mark with cell phone systems running Windows Mobile. While a considerable number of Japanese handsets do run on Symbian or Linux, they are locked down so users cannot add additional programs.
Things have been slowly changing and in the last couple of years Taiwan's High-Tech Computer has had success selling Windows Mobile-based phones to all of Japan's cellular carriers. The first 3G Blackberry service was launched by NTT DoCoMo last year and this year's launch of the iPhone has raised the profile of smartphones.
Use of the iPhone by BearingPoint could help traditionally risk-averse Japanese companies to consider the handset alongside more business-orientated models like those from Blackberry or running Windows Mobile.
The iPhone 3G went on sale in Japan simultaneously with many other nations on July 11. Despite a rush by enthusiastic early customers to get their hands on the iPhone, excitement for the handset has waned and the waiting lists of the launch period are now gone, although the iPhone's 2G version wasn't sold in Japan.