The Central District of Arak County () is in Markazi province, Iran. Its capital is the city of Arak.
After the 2006 National Census, Masumiyeh and Moshkabad Rural Districts were separated from the district in the formation of Masumiyeh District. Hajjiabad Rural District was created in the Central District, and Saruq Rural District was separated from it to form Saruq District.
After the 2011 census, the cities of Karahrud and Senjan were merged with the city of Arak.
At the time of the 2006 census, the Central District's population was 543,859 in 150,880 households. The following census in 2011 counted 571,933 people in 174,305 households. The 2016 census measured the population of the district as 565,357 inhabitants in 179,582 households.