He won the first race with 88 votes against his closest rival Trade Minister Penny Mordaunt and Foreign Secretary Liz Truss could get 67 votes and 50 votes respectively as they finished the first race in second place and third place.
Chancellor Nadhim Zahawi finished the race in fourth place, while former health secretary Jeremy Hunt was eliminated from the race and now he is backing Rishi Sunak.
There will be another round of voting on Thursday.
Rishi Sunak is a son-in-law for Infosys Founder Mr Narayan Muthry and writer Sudha Murthy as he is married to their only daughter Ms Akshata Murthy. Rishi and Akshata have two young daughters.
The race may be narrower among the first two contenders by next week. They may have to win support from other contenders and their members to become the next party leader and prime minister.
The final result will be announced on 5 September.