The tech giant has invented a pocket-sized device, named the Reon Pocket, which works by being inserted into a pocket in a specially made shirt to go underneath normal clothing.
The battery can last for up to 90 minutes, and only requires two hours charging time.
The temperature is controlled by a smartphone app.
Sony are hoping to officially launch the product in Japan in 2020 to coincide with the Tokyo Olympics.
It has a price tag of £100.