Vehicular air bag device

In a vehicular air bag device which has a door member (13) that is disposed on the rear face of an air bag lid portion (5), and that is pressed by an inflation pressure of an air bag body to be swung via a hinge portion, thereby forming an inflation opening in the air bag lid portion (5), a first hinge portion (30) and a second hinge portion (32) are disposed as the hinge portion. The second hinge portion (32) is bent in a stage where the inflation pressure of the air bag body is lower than a predetermined value, to cause formation of the inflation opening to be started.