 was a paleontologist and geologist.
Ishijima was one of the most prolific researchers of fossil calcareous algae. After graduating from the Imperial Fisheries Institute (Tokyo; current Tokyo University of Marine Science and Technology) in 1927, Ishijima joined the Institute of Geology and Paleontology, Faculty of Science, Tohoku Imperial University (Sendai) from 1927–1931. He then worked at the Institute of Geology, Taihoku Imperial University (Taipei) during 1942–1945 and then at the Rikkyo University (Tokyo) from 1945–1980. His doctoral dissertation was submitted to Tohoku University and was privately published by Yūhodō (Ishijima, 1954). He described a total of 139 taxa of fossil calcareous algae (Iryu, 2004) including at least 114 species of Corallinales, and he produced more than 45 publications on coralline algal taxonomy.