A blender comprising: a container body for receiving food; a main body for receiving and supporting the container body; a knob provided at the main body and configured to receive rotation manipulation for operating the blender; a main PCB module in the main body, wherein the knob is coupled to the main PCB module; and a misassembly prevention means (690, 691, 692, 693) provided at the knob and the main PCB module for guiding the knob to be coupled to the main PCB module in a predetermined orientation; wherein the misassembly prevention means comprises: a guiding protrusion (690, 691), and a guiding hole (692, 693) configured to receive the guiding protrusion (690, 691), wherein one of the guiding protrusion (690, 691) and the guiding hole (692, 693) is provided on the main PCB module, and the other of the guiding protrusion (690, 691) and the guiding hole (692, 693) is provided on the knob; wherein the guiding protrusion (690, 691) includes a plurality of guiding protrusions (690, 691) and the guiding hole (692, 693) includes a plurality of guiding holes (692, 693); characterized in that the plurality of guiding protrusion (690, 691) includes at least two guiding protrusions (690, 691) having shapes and/or sizes different from each other, and wherein the plurality of guiding holes (692, 693) includes at least two guiding holes (692, 693) having shapes and/or sizes different from each other, and wherein one of the at least two guiding protrusions (690, 691) has a shape and/or a size selectively corresponding to a shape and/or a size of one of the at least two guiding holes (692, 693), and wherein the other of the at least two guiding protrusions (690, 691) has a shape and/or a size selectively corresponding to a shape and/or a size of the other of the at least two guiding holes (692, 693). a container body for receiving food; a main body for receiving and supporting the container body; a knob provided at the main body and configured to receive rotation manipulation for operating the blender; a main PCB module in the main body, wherein the knob is coupled to the main PCB module; and a misassembly prevention means (690, 691, 692, 693) provided at the knob and the main PCB module for guiding the knob to be coupled to the main PCB module in a predetermined orientation; wherein the misassembly prevention means comprises: a guiding protrusion (690, 691), and a guiding hole (692, 693) configured to receive the guiding protrusion (690, 691), wherein one of the guiding protrusion (690, 691) and the guiding hole (692, 693) is provided on the main PCB module, and the other of the guiding protrusion (690, 691) and the guiding hole (692, 693) is provided on the knob; wherein the guiding protrusion (690, 691) includes a plurality of guiding protrusions (690, 691) and the guiding hole (692, 693) includes a plurality of guiding holes (692, 693); characterized in that the plurality of guiding protrusion (690, 691) includes at least two guiding protrusions (690, 691) having shapes and/or sizes different from each other, and wherein the plurality of guiding holes (692, 693) includes at least two guiding holes (692, 693) having shapes and/or sizes different from each other, and wherein one of the at least two guiding protrusions (690, 691) has a shape and/or a size selectively corresponding to a shape and/or a size of one of the at least two guiding holes (692, 693), and wherein the other of the at least two guiding protrusions (690, 691) has a shape and/or a size selectively corresponding to a shape and/or a size of the other of the at least two guiding holes (692, 693). a guiding protrusion (690, 691), and a guiding hole (692, 693) configured to receive the guiding protrusion (690, 691), wherein one of the guiding protrusion (690, 691) and the guiding hole (692, 693) is provided on the main PCB module, and the other of the guiding protrusion (690, 691) and the guiding hole (692, 693) is provided on the knob; wherein the guiding protrusion (690, 691) includes a plurality of guiding protrusions (690, 691) and the guiding hole (692, 693) includes a plurality of guiding holes (692, 693); characterized in that the plurality of guiding protrusion (690, 691) includes at least two guiding protrusions (690, 691) having shapes and/or sizes different from each other, and wherein the plurality of guiding holes (692, 693) includes at least two guiding holes (692, 693) having shapes and/or sizes different from each other, and wherein one of the at least two guiding protrusions (690, 691) has a shape and/or a size selectively corresponding to a shape and/or a size of one of the at least two guiding holes (692, 693), and wherein the other of the at least two guiding protrusions (690, 691) has a shape and/or a size selectively corresponding to a shape and/or a size of the other of the at least two guiding holes (692, 693).