Graham Stuart has quit his role as Minister of State for Energy Security and Net Zero after nearly 18 months in the role.
The MP for Beverley and Holderness has been replaced by former deputy Tory chairman Justin Tomlinson.
Mr Stuart had been made a cabinet minister by Liz Truss in September 2022 and Minister of State for Climate.
The role lasted barely two months, though his portfolio was extended to include the energy brief when Mr Sunak took over, though he lost his cabinet position.
In his resignation letter to Prime Minister, he said: "I'm proud of all we have achieved as a government, not least being the first major economy to halve CO2 emissions.
"Under your leadership the UK is at near full employment, has inflation falling fast and is set to go from strength to strength in the coming years."
He added that he wants to concentrate more of his time on local issues.
In a letter accepting his resignation, Mr Sunak paid tribute to him, saying: "You have played a crucial role in making sure that this country and our industries are well prepared for the growth opportunities that the energy transition will provide."