A steering system comprising: a steering shaft that is configured to contract and extend in a column axial direction; a column jacket that includes a lower jacket and an upper jacket fitted to the lower jacket and that supports the steering shaft so that the steering shaft is rotatable, the column jacket being configured to contract and extend in the column axial direction; a first tooth defining member having a plurality of first teeth such that the first teeth are arranged in the column axial direction, the first tooth defining member moving together with the upper jacket; a support shaft that is supported by the lower jacket or a member supported by the lower jacket and that extends in an orthogonal direction orthogonal to the column axial direction; a second tooth defining member that has second teeth configured to come into meshing engagement with the first teeth, that is supported by the support shaft so as to be rotatable around a central axis of the support shaft, characterised in that the second tooth defining member is detached, at a time of a secondary collision, from the lower jacket with the second teeth kept in meshing engagement with the first teeth; and in that the steering system further comprises an energy absorbing unit including a pair of energy absorbing portions each including a restraining portion restrained in the column axial direction by the lower jacket, a first portion extending upward from the restraining portion in the column axial direction, a fold-back portion, and a second portion formed by folding back the energy absorbing portion at the fold-back portion, the energy absorbing portions being separated from each other in the orthogonal direction, and a coupling portion that couples the second portions of the energy absorbing portions together and that moves together with the second tooth defining member at the time of the secondary collision, wherein at the time of the secondary collision, the energy absorbing portions allow the fold-back portions to move downward in the column axial direction to absorb impact energy while guiding downward movement of the second tooth defining member in the column axial direction between facing edges of the energy absorbing portions. a steering shaft that is configured to contract and extend in a column axial direction; a column jacket that includes a lower jacket and an upper jacket fitted to the lower jacket and that supports the steering shaft so that the steering shaft is rotatable, the column jacket being configured to contract and extend in the column axial direction; a first tooth defining member having a plurality of first teeth such that the first teeth are arranged in the column axial direction, the first tooth defining member moving together with the upper jacket; a support shaft that is supported by the lower jacket or a member supported by the lower jacket and that extends in an orthogonal direction orthogonal to the column axial direction; a second tooth defining member that has second teeth configured to come into meshing engagement with the first teeth, that is supported by the support shaft so as to be rotatable around a central axis of the support shaft, characterised in that the second tooth defining member is detached, at a time of a secondary collision, from the lower jacket with the second teeth kept in meshing engagement with the first teeth; and in that the steering system further comprises an energy absorbing unit including a pair of energy absorbing portions each including a restraining portion restrained in the column axial direction by the lower jacket, a first portion extending upward from the restraining portion in the column axial direction, a fold-back portion, and a second portion formed by folding back the energy absorbing portion at the fold-back portion, the energy absorbing portions being separated from each other in the orthogonal direction, and a coupling portion that couples the second portions of the energy absorbing portions together and that moves together with the second tooth defining member at the time of the secondary collision, wherein at the time of the secondary collision, the energy absorbing portions allow the fold-back portions to move downward in the column axial direction to absorb impact energy while guiding downward movement of the second tooth defining member in the column axial direction between facing edges of the energy absorbing portions.