The present invention relates to a novel dermal filler composition and to a method for preparing same. The composition of the present invention comprises, as a main component, cross-linked dextran, the molecular weight of which is 30,000 to 100,000. The composition can rapidly augment a defective area of the skin and maintain softness to the touch even when used alone. The composition eliminates the necessity of a pretreatment, such as an allergy test, which might otherwise be required prior to injection, is inexpensive, and is not easily decomposed or absorbed in vivo, thereby maintaining the tissue-volume augmentation effects thereof over a long period of time after injection. Therefore, the composition is suitable for use in a procedure such as penile augmentation or the like which requires the injection of a large amount of dermal filler, i.e. more than 20 cc. The composition of the present invention can be prepared through a simplified process to make the composition easily usable. The composition is soft to the touch when injected under the skin, and can thus be applicable not only to the skin of the penis but also to the skin of other parts of the human body, Including the face.