Constant tensile load testing machine

The utility model provides a constant tensile load testing machine. The constant tensile load testing machine comprises a rack, a lever, a weight and a loading rod, a bearing seat is arranged on the side part of the rack; the lever is hinged to the upper end of the rack through a hinge shaft and is provided with a loading end and a bearing end, the loading end is provided with a first arc-shaped surface, and the bearing end is provided with a second arc-shaped surface; the weight is connected to the loading end through a first rope body; the loading rod is connected to the bearing end through a second rope body, and a loading seat is arranged at the lower end of the loading rod. According to the constant tensile load testing machine provided by the utility model, the weight is arranged at the loading end of the lever, so that the tensile force of the loading end is multiplied, the implementation of a larger loading force value can be realized through the weight with smaller weight, and when a tested sample is