Naojiro HARADA was born as the second son of Ichido HARADA, who was a Bansho-wage Goyo Shutsuyaku (government officer for the translation of foreign books), and his wife Ai at his mother's family home in Koishikawa in Edo.
1863年8月30日、蛮書和解御用出役の原田一道と妻あいの次男として、江戸小石川の母の実家で誕生した。