The utility model relates to a pressure device, in particular to a pressure control device for controlling the pressure of a furnace chamber of a silicon carbide furnace. The silicon carbide furnace comprises a silicon carbide furnace cavity, and the silicon carbide furnace cavity is provided with a cavity air inlet and a cavity air outlet; the cavity air outlet is connected with one end of a mainvacuum pipeline; the other end of the main vacuum pipeline is connected with the vacuum pump; a vacuum valve and a bypass branch are arranged on the main vacuum pipeline; the bypass branches are a plurality of pressure control branches connected in parallel, and each pressure control branch is provided with a vacuum valve; the diameter of each pressure control branch is smaller than that of the main vacuum pipeline, and the diameters of the pressure control branches are different. Due to the fact that the device has several paths of pipe diameters with different sizes, the ventilation capacity is adjustable, the size and the number of the pipe diameters can be improved according to actual use experience, and the pressure in the cavity can be easily balanced in the inert gas filling and sucking process in cooperation with frequency conversion of the vacuum pump.