A self-adaptive rotary arm positioning device, comprising a rotary arm body (1) and a vibration isolating cushion (2). One end of the rotary arm body (1) is rotatably connected to a frame of a bogie by means of a rotary arm joint (3), and an upper surface (4) of the other end is connected to a lower surface (5) of the vibration isolating cushion (2). The upper surface (4) and the lower surface (5) have a vertical distance therebetween, and are in rolling fit with a curved member (6) at least in front and rear directions. The vertical distance is used for providing space for the rotation of the other end of the rotary arm body (1) about the rotary arm joint; or, the upper surface (4) and the lower surface (5) are matching arc-shaped surfaces or spherical surfaces, and the arc-shaped surfaces or the spherical surfaces extend from front to back. The extending length of the upper surface (4) in the front and rear directions is greater than the extending length of the lower surface (5) in the front and rear directions. Also disclosed is a bogie. The bogie and the self-adaptive rotary arm positioning device thereof can provide space for the rotation of the other end of the rotary arm body about the rotary arm joint.