Prime Minister Rishi Sunak was fined for not wearing a seatbelt while making a social media video in a moving car.
Lancashire Police said it had made a conditional offer of a fixed penalty to a 42-year-old man from London.
Mr Sunak "fully accepts this was a mistake and has apologised," according to No. 10, adding that he will pay the fee.
Passengers who fail to use a seat belt when one is provided face a £100 fine.
If the matter gets to court, the fine may rise to £500.
The video was shot in Lancashire as the prime minister was on a journey through the north of England.
The video was released on Mr Sunak's Instagram account to promote the government's newest round of "levelling up" spending.
Mr Sunak has gotten a fixed penalty notice twice while in office.
Last April, he and Boris Johnson were punished for violating Covid lockdown restrictions by attending a birthday party for the then-prime minister in Downing Street in June 2020.
Fixed penalty notifications are a type of fine that must be paid or disputed within 28 days of receiving the notice.
If a person chooses to challenge the fine, the police will investigate the situation and determine whether to rescind the fine or take the matter to court.
Labour's deputy leader, Angela Rayner, called Mr Sunak a "total liability" in a tweet.
"Hapless Rishi Sunak's leveling-up photo op has blown up in his face and turned him into a laughing stock," a Labour Party official remarked.
The Liberal Democrats claimed he had "shown the same disregard for the rules as Boris Johnson" by becoming the second prime minister in history to be fined by police.
"From partygate to seatbeltgate, these Conservative politicians are just taking the British people for fools," said Daisy Cooper, deputy Lib Dem leader.
"Whilst they continue to behave as though it’s one rule for them and another for everyone else, this fine is a reminder that the Conservatives eventually get their comeuppance."
But Conservative MP for Blackpool South Scott Benton defended Mr Sunak, saying "everybody makes mistakes".
Mr Benton said police should focus on "tackling serious crime in our communities", adding: "Let’s keep this in proportion here. Every single year millions of Britons receive similar fixed penalty notices."
Passengers aged 14 and over are responsible for wearing a seat belt in cars, vans, and other goods vehicles if one is provided. Drivers are liable for passengers under the age of 14.
Exemptions include possessing a doctor's certificate for a medical reason or being in a vehicle utilised by law enforcement, fire, or other rescue services.