A knee airbag device includes a column cover that covers a rear end portion of a steering column from below; and an airbag module. The airbag module is disposed in a column lower cover and includes a gas generation portion that generates gas and a knee airbag that is housed in the airbag module in a folded state, and is inflated and deployed by the gas supplied by the gas generation portion. The airbag module is connected to the steering column by a snap-fit action.