A tilt-up mechanism for tilting up an upper column of a steering column from a drive position to a tilt-up position is configured independently from a tilt angle adjusting mechanism and a column length adjusting mechanism. When an operator who is to get on/off an operator's seat steps on and operates a pedal of the tilt-up mechanism, an engaged state of a lock pin with respect to a tilt-up member is disengaged. The tilt-up member is rotated around a support shaft, by a spring force of a tilt-up spring, whereby the upper column is tilted up together with a steering wheel in a direction (A) away from the operator's seat. At this time, the tilt angle and the column length can be held at positions adjusted in advance.