The invention discloses a fixed-length cutting device for tubes. The fixed-length cutting device comprises a cutting table, a cutting device, support elements, a location table, a support shaft, a location disc and baffles, wherein the cutting device is arranged at the front end of the cutting table; the plurality of support elements are arranged on the cutting table along the same straight line, wherein the support element at the forefront is located in front of the cutting device; the location table is arranged in front of the cutting table; the support shaft is erected on the location table in a manner of being capable of sliding forwards and backwards; the location disc is rotatably arranged at the rear end of the support shaft in a sleeving manner, a plurality of U-shaped grooves are arranged in the rear end surface of the location disc in a sinking manner along a peripheral direction, and the opening of each U-shaped groove penetrates through the sidewall of the location disc; one baffle is arranged at the opening of each U-shaped groove in a covering manner; and one end of each baffle is hinged at one side of the opening of the corresponding U-shaped groove through a pin shaft, and a torsional spring is arranged on each pin shaft in a sleeving manner. The fixed-length cutting device disclosed by the invention is capable of conveniently carrying out fixed-length cutting on the tubes, safe and efficient in cutting process, and low in cost.