The invention provides an automatically ignited microwave plasma torch device. The automatically ignited microwave plasma torch device consists of an outer tube, an intermediate tube, an inner tube, a space ring, a microwave coupling interface, an outer tube microwave opening, a coupling rod, a coupling ring, a reflection end face, and a regulating piston. The microwave plasma torch is formed by a section of the opened metal coaxial resonant cavity of three coaxial tubes, and the microwave is used for forming the plasma torch at the opening end. The automatically ignited microwave plasma torch device is capable of changing the ignition mode of the microwave plasma torch, and enabling the torch tube to realize the autoignition without an additional device through regulating the relative position of the inner tube of the torch tube, so the usability of the microwave plasma torch device is greatly enhanced, the effect of a high-pressure ignition needle to the design of the microwave shielding structure can be eliminated, the device structure is simplified, and the reliability and the stability of the device are enhanced. The microwave plasma torch is used for the plasma source for the analysis of the atomic emission spectroscopy, and also used for the plasma source for the technical field of the chemistry and measurement.