A steering device according to an aspect of the present invention includes an outer shaft, an inner shaft, an outer column, and an inner column. The inner shaft has a sliding portion configured to be capable of being inserted into the outer shaft, and a bearing-mounting portion that is connected to the sliding portion in an axial direction thereof and is configured not to be capable of being inserted into the outer shaft. In the bearing-mounting portion, rear bearings are disposed with an interval therebetween in the axial direction.