A cooking appliance comprising a front panel that forms a front side of the appliance and a knob assembly, the knob assembly comprising: a knob located at a front side of the front panel and configured to rotate based on operation by a user; a knob shaft that is coupled to the knob and that extends through the front panel ; a supporting pipe that receives and supports the knob shaft , the supporting pipe being configured to maintain a position thereof relative to the front panel ; a valve located in the appliance and configured to control supply of gas to the appliance; a valve shaft connected to the valve and configured to control the valve to adjust a flow rate of gas based on rotation of the valve shaft; and a joint that couples the knob shaft to the valve shaft and that is configured to transfer a rotational motion and a linear motion of the knob shaft to the valve shaft , characterized by : a case assembly comprising the knob , a knob ring , a spacing plate , a locking bracket , a support frame , a spacing pipe , an actuating member , a fixed frame , and a fixed pipe , the knob , the knob ring , the spacing plate , and the locking bracket are arranged outside the front panel , the support frame , the spacing pipe , the actuating member , and the fixed frame , and the fixed pipe are arranged inside the front panel , the fixed pipe is fastened to the rear surface of the fixed frame , the fixed pipe serves to support the knob shaft provided on the knob and guide the assembly of the joint . a knob located at a front side of the front panel and configured to rotate based on operation by a user; a knob shaft that is coupled to the knob and that extends through the front panel ; a supporting pipe that receives and supports the knob shaft , the supporting pipe being configured to maintain a position thereof relative to the front panel ; a valve located in the appliance and configured to control supply of gas to the appliance; a valve shaft connected to the valve and configured to control the valve to adjust a flow rate of gas based on rotation of the valve shaft; and a joint that couples the knob shaft to the valve shaft and that is configured to transfer a rotational motion and a linear motion of the knob shaft to the valve shaft , characterized by : a case assembly comprising the knob , a knob ring , a spacing plate , a locking bracket , a support frame , a spacing pipe , an actuating member , a fixed frame , and a fixed pipe , the knob , the knob ring , the spacing plate , and the locking bracket are arranged outside the front panel , the support frame , the spacing pipe , the actuating member , and the fixed frame , and the fixed pipe are arranged inside the front panel , the fixed pipe is fastened to the rear surface of the fixed frame , the fixed pipe serves to support the knob shaft provided on the knob and guide the assembly of the joint . a case assembly comprising the knob , a knob ring , a spacing plate , a locking bracket , a support frame , a spacing pipe , an actuating member , a fixed frame , and a fixed pipe , the knob , the knob ring , the spacing plate , and the locking bracket are arranged outside the front panel , the support frame , the spacing pipe , the actuating member , and the fixed frame , and the fixed pipe are arranged inside the front panel , the fixed pipe is fastened to the rear surface of the fixed frame , the fixed pipe serves to support the knob shaft provided on the knob and guide the assembly of the joint . <EOS>