A radial driving force based rotary guide device comprises a rotating shaft and a non-rotary part. The rotating shaft rotationally drives a tool bit and comprises an upper shaft portion, a lower shaftportion and a rotatable portion, and the upper shaft portion and the lower shaft portion are in rotatable connection through the rotatable portion. The non-rotary part is mounted on the upper shaft portion and is peripherally in a non-rotary state relative to the rotating shaft when the rotating shaft rotationally drives the tool bit. The lower shaft portion comprises a rib portion which is at least partially and axially coincided with the non-rotary part. The non-rotary part comprises at least three hydraulic driving mechanisms in uniform distribution peripherally, the at least three hydraulic driving mechanisms are suitable for controllable generation of radial driving force, and the radial driving force acts on the rib portion coincided with the non-rotary part so as to enable the lower shaft portion to deflect relative to the rotatable portion.