Column-mounted knee airbag device

A column-mounted knee airbag device in which a knee airbag can be correctly deployed even when the position of a steering column has changed due to a telescopic function. The column-mounted knee airbag device is equipped with a knee airbag folded inside a column cover covering a steering column main body having a telescopic function, and an inflator that generates gas when a vehicle impact is detected or predicted. The knee airbag opens an airbag door of a column cover by deployment pressure when supplied with gas, and deploys between an instrument panel and the knees of a driver. Gas ejection holes that supply gas from the inflator to the knee airbag are disposed, when viewed from the side with the steering column in a state positioned furthest to the front due to a telescopic function, further to the rear than the instrument panel in the vehicle front-rear direction.