Provided is an occupant protection device which is disposed together with an under-cover of an instrument panel, has a harness connected to an inflator and protects a knee portion of an occupant, including a case in which a first surface is disposed along a lower end of the under-cover and the harness is disposed on a side surface intersecting the first surface and extending in forward and backward direction of a vehicle, and an overhanging portion configured to protrude from a side surface of the case on a lower side of the harness in a vehicle width direction.