PURPOSE: To provide a steering device for a trailer which improves safety during driving and simplifies loading works on a load-carrying platform by lowering the height of the device itself as low as possible.

CONSTITUTION: A king pin is constituted in such a way as rotating by a turntable having the king pin as a center according to rotation of the tractor, the other end of a lever of which one end is fixed to the rotation center of the turntable is rotatably journaled to one end of a sliding handle 20 in which a long hole is transparently provided, an equalizer 26 into which the sliding handle is inserted and which is provided with a shaft 24 penetrating through the long hole of the sliding handle is constituted, and a support plate 28 fixed to the equalizer is rotatably pivoted to one end of a coupling rod constituting a link mechanism. It is characterized that rotation displacement of the tractor is transmitted to the rear wheel shaft by the link mechanism so that sectional forms of the sliding handle and the equalizer comprising a transmission part of rotation displacement of the steering device are formed into long sideways rectangle.