The present invention relates to a water-soluble dry food containing a plant-origin material as the main ingredient and water-soluble dietary fiber as an additive. The water-soluble dry food of the present invention further contains edible oil. Preferably, as the edible oil, use is made of olive oil, safflower oil, sesame oil or rapeseed oil. Preferably, ashitaba is used as the plant-origin material, whereas indigestible dextrin is used as the water-soluble dietary fiber.