Aridagawa (有田川町, Aridagawa-chō) is a town located in Arida District, in central Wakayama Prefecture, Japan.

Aridagawa was established on January 1, 2006, by the merger of the towns of Kanaya, Kibi and Shimizu, all from Arida District.

Aridagawa has a mayor-council form of government with a directly elected mayor and a unicameral city council of 16 members.

Hidaka collectively with the other municipalities of Arida District, contributes two members to the Wakayama Prefectural Assembly.

In terms of national politics, the town is part of Wakayama 3rd district of the lower house of the Diet of Japan.