A centrifugal fan is disclosed and includes a lower case, an impeller and an upper case. The lower case includes a bottom plate and a sidewall. The impeller is disposed on the bottom plate. The upper case is assembled with the sidewall to form an outlet. The upper case is formed by stamping and includes a first plane, an inlet and a grille. When the impeller is rotated, an airflow flowing from the inlet to the outlet is formed. The grille is protruded outwardly from the first plane, and includes a connecting frame and plural ribs. A spacing height is formed between the connecting frame and the inlet. Each rib has a first end connected to the connecting frame and a second end connected to the first plane. A pair of notches are disposed adjacent to two opposite lateral edges of the second end of the corresponding rib, respectively.