PURPOSE: To make it possible to freely move a traveler on a flat place and as well on stairs, by providing, in the center body of the traveler, at least three legs which are retractable or foldable.

CONSTITUTION: Legs 4, 4 are held in the same condition while a traveler as a whole is set in its stable condition, and wheels 3, 13 are rotated in the same direction to move the traveler. In order to setp up the stairs 51, at first one of legs 4 is lifted up to set on a stair 51a. In this stage, the first and second legs of them are folded and/or the second leg is exteneded. When the legs are exteneded and retracted or folded, an attitude holding mechansm maintains a carrier, horizontally. Thereby a storing mechanism 28 may be moved while it is held in its vertical position. Further, the other two legs 4, 4 positioned in the lower stair 51 together with a center traveler body 1 are made climb up the next stair 51a one by one. With this arrangement, such a condition is always maintained that three points are stationary and the remaining one point is on moving, thereby the traveler may stably move and step up the stairs.