Myōjin-shō (明神礁) is a submarine volcano located about 450 kilometers south of Tokyo on the Izu-Ogasawara Ridge in the Izu Islands.

The name Myōjin-shō derives from a fishing boat, No.11 Myōjin-Maru of Yaizu City, Shizuoka Prefecture, the crew of which first witnessed the major volcanic eruption of 1952.

5 of the Hydrographic Department of the Maritime Safety Agency, was destroyed by the volcano, with the loss of its crew of 31 (including the nine scientists studying the eruption).

Consequently, the Department developed Manbou (Sunfish), an unmanned radio operating survey boat, and has used it for the research of dangerous sea areas such as submarine volcanoes.

A record that suggests a gushing of bubbles near the summit was obtained and micro-earthquakes were observed near Myōjin-shō, showing that the volcano is still active, although at a low level