Masashi Mito (水戸 将史? Mito Masashi, born July 28, 1962) is a Japanese politician of the Democratic Party of Japan, a member of the House of Councillors in the Diet (national legislature). A native of Tomamae District, Hokkaidō and 1985 graduate of Keio University, he was elected to the House of Councillors for the first time in 2007 after serving in the assembly of Kanagawa Prefecture for three terms from 1995 until 2007.