Baron Hidaka Sōnojō (日高 壮之丞, 26 April 1848 – 24 July 1932) was an admiral of the early modern Imperial Japanese Navy, known primarily for his role in the First Sino-Japanese War.

In 1870, he enrolled in the 2nd class of the Imperial Japanese Naval Academy and as a cadet was part of the team which brought the corvette Tsukuba from its shipyards in England back to Japan in 1871.

Over the next 20 years, he rose steadily through the ranks, serving on the paddle steamer warship Kasuga (1876), corvette Nisshin (1876), Fusō (1878),Kenko (1879), Ryūjō (1880), and Asama (1881).

In 1882, he was assigned to the Shipbuilding Bureau of the Imperial Japanese Navy General Staff, but continued to simultaneously serve on Fusō (1884) and Amagi (1884) and Seiki (1885).

In the semi-historical television adaption of Ryōtarō Shiba’s Saka no ue no kumo role of Hidaka was played by veteran actor Akira Nakao