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 (124c, 124f) 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 (124c, 124f) 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.