To provide a telescopic steering device preventing rotational motion of a movable bracket to a fixed bracket in a telescopic action, causing no unusual noise or a response delay, and smoothly carrying out a telescopic action.

In the outer circumference part fitted in a lower tube of the telescopic tube 21, a flat plane part 21a is arranged in at least one position, and a flat plane end part 15a of a contact member 15 fixed to the lower tube 11 is brought into contact with the flat plane part 21a with a predetermined pressing force, while a nut meshed with a screw 45 connected to an output shaft of a motor 42 is arranged inside a housing 48 fixed to the telescopic tube 21 movably only in the radius direction via a rubber bush 51.