It is Koppe pan
"Koppe-pan is a spindle-shaped bread that can be held with one hand and has a flat bottom. Bread unique to Japan.
The shape is similar to French "coupé (e)" bread and hot dog buns found in the United States, but in the late Meiji era, he learned how to make bread in the United States and was in the Taisho era. This bread was devised by Genpei Tanabe, who developed the first bread making method using yeast in Japan, and has developed uniquely to Japan. "