First Computer with Mouse - The Xerox 8010
Although keyboards have been with us since some of the earliest days of the compute age, mice as common input devices took a significantly longer time to ship bundled with computers let alone become ubiquitous. Early computers had mice and mouse-like input devices, but they were exclusively aftermarket add-ons and did not ship with the computer the German Telefunken computer is an example of an early computer that had a mouse that integrated with the system but was an accessory and not an included peripheral.
The earliest computer to ship with a mouse as part of the system was the Xerox 8010 Star. Released in 1981, the system came with a two-button serial mouse; the mouse was lightweight, sported an optical sensor instead of a roller ball, and it didn't require a mouse pad much like modern infrared/laser mice.