Yuuichirou Tomonaga is a character in the Brave Police J-Decker series. 


Yuuichirou Tomonaga is the father of Yuuta, Azuki, and Kurumi, and the husband of Amami. He works as a archaeologist for the Japanese government along with his wife, which requires them to travel extensively. This typically leaves all three children at home by themselves with Azuki in charge.

After finishing up an expedition to the southern island of Hedro, he and his wife returned to Japan to visit their family and meet Deckerd as well as discuss Yuuta's involvement with the Brave Police. He brought with him a statue given to him by the natives of Hedro Island, which turned out to have a larval Cabalientro baraelicatodomes (giant moth) inside. Yuuichirou attempted to help the Brave Police contain the giant insect as it ran amok in the city and then morphed into its final life stage, a giant moth with corrosive scales. Later, he expressed regret at its demise and stated he would have rather seen the city destroyed than have it die.

Before leaving with his wife on a new expedition, they both elected to spend a lot of time with their children, particularly Yuuta, which made Deckerd feel jealous and left out. When Deckerd disappeared after attempting to follow up on a case by himself, Yuuichirou joined in the search for him, and defended him from the criminals when they attempted to destroy him, claiming Deckerd as a member of the Tomonaga family.