A case of an extending base for an electronic device includes a body, a cover, and at least two link elements. The body has a hollow. The cover is disposed aside the hollow. Each link element has a first pivot part, a first block part, a second pivot part, and a first elastic member. The first pivot part has a first end pivoted on the body and a second end connected to the first block part. The second pivot part has a first end pivoted on the cover and a second end connected to the first block part. The first elastic member provides a force to push the first block part from a first position to a second position so as to correspondingly push the cover. Herein, when the first block part is positioned at the first position, the first block part is separated from the body and the cover covers the body. In addition, when the first block part is positioned at the second position, the first block part is in contact with the body and the cover is separated from the body.