An elliptical trainer comprises a reciprocal-movement mechanism and an angle-adjusting chassis. The angle-adjusting chassis comprises a frame, a guider, an angle-adjusting assembly, and an intermediary part. Both the front end of the frame and the rear end of the guider may contact a supporting surface, and the rear portion of the frame may be pivotally coupled with a front portion of the guider. The angle-adjusting assembly is arranged near the rear portion of the frame, and the intermediary part is arranged at or near or attached to the front portion of the guider. The angle-adjusting assembly pushes the intermediary part, such that the guider rotates around its rear end, and the frame rotates around its front end, resulting in varying a first angle between the guider and the supporting surface and varying a second angle between the frame and the supporting surface.