Airbag cover, airbag module

To provide a rational technology for configuring an airbag cover for covering a vehicle's airbag. An airbag cover 100 is provided with a tear line 102, an open-out door panel 100a which is openable when the tear line 102 is torn, a thinned portion 120 formed in the boundary area between the main body of the airbag cover and the open-out door panel 100a on the back surface 101 of the cover, and a second rib 130 extending in the direction intersecting the extending surface of the open-out door panel 100a between the main body of the airbag cover and the open-out door panel 100a. The airbag cover 100 is configured such that the extending length of the portion on which the second rib 130 is provided is larger than the wall thickness of the respective portions on the side of the open-out door panel 100a with respect to the second rib 130 (Fig. 6).