Sleeping bag for infants

The utility model relates to a sleeping bag for infants. The sleeping bag comprises an upper material layer (1), a lower material layer (2), wherein the upper material layer (1) is connected with the lower material layer (2); the top part of the body formed by connecting the upper material layer (1) with the lower material layer (2) is provided with an opening (4), and an inner space which is gradually widened from the top part to the bottom part is formed between the upper material layer (1) and the lower material layer (2); the inner space (height) of the sleeping bag for the infants is widened from the head to the feet to form an inner space which is gradually heightened, when the infant sleeps in the sleeping bag, the chest of an infant is properly located in the narrow part of the space (the position does not need large space, because the sleeping bag cannot be tightly covered if the space is large); and the feet are located at the higher space, so that the feet of the infant can freely move and cannot b