For rapid information gathering in case of disaster, various unmanned search/rescue robots have been developed. It is difficult to respond to complex condition of a field where requires some locomotion strategies for most robots having only one kind of locomotion mechanism. To increase search routes in a such condition to aim gathering information more rapidly, we proposed the legged air vehicle: This vehicle has four legs to walk and two rotors to fly. The feature of the vehicle is fewer actuators than sum of those of a quadrupedal walking robot and a tandem rotor type helicopter. This paper presents a model and an attitude control system using leg motion of the vehicle, and simulations of the motion when attitude controlling by Multibody Dynamics software.