Hitachi had planned for the product to go on sale by the end of 2001.
The wearable PC includes a head-mounted display unit that lets a person view a high-resolution image, while the rest of the device is small enough to slip into a pocket. Hitachi believes that people will use the wearable PC to work, surf the Web or play games when they're not at home or in the office.
Hitachi developed the wearable PC in collaboration with Xybernaut, a U.S. company that has developed a range of similar products.
Japanese customers will buy the wearable PC from Hitachi, which calls it the WIA-100NB Wearable Internet Appliance.
Xybernaut, which will target U.S. consumers, has called the device the "Poma" and is already taking orders on its Web site. The Poma will cost $1,499.
The wearable PC runs on Microsoft's Windows CE operating system and contains a Hitachi 128MHz Risc processor and 32MB of RAM. It will also offer slots for CompactFlash cards and USB.
The headset will give people the illusion of a 13-inch color screen in front of their face. The machine is operated via a hand-held optical mouse.
Xybernaut already sells a number of wearable applications that are used by workers in sectors such as aerospace and travel.
Graeme Wearden reported from London.