Speed-changing gear box angle loss measuring instrument

The invention provides a gearbox angle loss measuring instrument which comprises a supporting base, the supporting base is provided with a rotation stopping structure matched with a transmission shaft of a gearbox in a rotation stopping mode, the supporting base is further provided with an angle measuring scale, the angle measuring scale is provided with a vertical measuring face facing an output shaft, and the vertical measuring face is provided with angle marks; the gearbox angle loss measuring instrument further comprises a measuring pointer installed on the output shaft, and the angle measuring scale is matched with the measuring pointer so as to observe the rotation angle of the output shaft when torque is applied to the input shaft of the gearbox. According to the invention, through deflection of the measuring pointer on the output shaft on the angle measuring scale, the angle loss value of the gearbox is directly read, the operation is simple, angle loss measurement can be accurately, rapidly and conve