The Bentley Mulsanne was part of the Royal Household for two years and was used to drive Her Majesty during her Diamond Jubilee celebrations.
The Queen also used the vehicle to attend 10 Downing Street, to meet with the Prime Minister.
A sales spokesman said: "This car presents a collector with the rare opportunity to purchase a car that has been used to good effect by our longest reigning monarch."
But the buyer will need to be ready to pay a big sum, as the car is on sale for Â£199,850.
A Royal car once used by the Queen has been put up for sale.