Arima was born in Tokyo as a son of the former daimyō of Kurume Domain (now part of Fukuoka Prefecture).

Arima founded the Nihon Nomin Kumiai (Japan Farmer's Union) together with Kagawa Toyohiko.

He was active in various social programmes, including the establishment and support of night school, women's education, farmer's rights, and the rights of the burakumin, and was chairman of a cultural association aimed at improving education and cultural awareness in rural areas.

In 1929, after he succeeded his father to the title of hakushaku (count) under the kazoku peerage system, he was nominated to the House of Peers.

In 1940, Arima became head of the Taisei Yokusankai organization, but resigned after five months due to opposition from the militarist faction in the government.