An occupant protection device includes: an airbag including an upper inflating portion and a lower inflating portion, and a rear inflating portion having a restraint surface that receives the occupant, the airbag being provided with a hollow portion penetrating in a left-right direction in a center; and a protrusion length adjustment unit configured to adjust a protrusion length from an accommodation position to the restraint surface in the airbag. An exhaust port configured to exhaust the inflation gas is disposed on an inner peripheral surface side in the vicinity of an intersection portion between the upper inflation portion and the lower inflation portion of the airbag. When the protrusion length by the protrusion length adjustment unit is adjusted to be long, the upper inflation portion and the lower inflation portion approach each other, so that an edge member approaches the exhaust port, thereby reducing an exhaust amount.