After serving in a number of administrative positions with the Imperial Japanese Army General Staff, Inada was assigned as a military attaché to France from 1929-1931.

From 1940 Inada was commanding officer of a heavy artillery regiment based in Acheng in northern Manchukuo.

[1] Inada was then sent as Vice Chief of Staff of the Southern Expeditionary Army Group in the Pacific Theater from 1942 to 1943.

Promoted to lieutenant general in April 1945, Inada was Chief of Staff of the 16th Area Army until the surrender of Japan.

He was found guilty of his complicity in the cover-up of the vivisection and other human medical experiments performed at the Kyushu Imperial University on downed Allied airmen.