This paper discusses a static stability theory for airplanes. The conventional definitions of static stability are neither clear nor systematic. For example, the aerodynamic characteristics that play an important part for obtaining static stability are used just like the definition of static stability. And, although the static stability concepts for flight-velocity and three rotary motions are discussed, the static stability concepts for heaving velocity (or angle of attack) and sliding velocity (or sideslip angle) are almost not discussed. On the basis of these situations, a system of definitions for 6 static stability concepts is proposed in this paper. In the first report of this paper, the static flight-velocity stability and the static angle of attack stability of these 6 stability concepts are discussed, and each stability criteria are obtained using the aerodynamic characteristics of airframe.