An image projection device comprising: a projector configured to project an image, and a main body housing the projector, an operation unit configured to receive an operation performed by an operator, a controller configured to control an operation of the projector, and a switching unit configured to switch whether to supply power from the controller to the projector in response to a pressing operation on the operation unit, a wired input receiver configured to receive as input a video by wire, and a wireless input receiver configured to receive as input a video by radio, wherein the projector is in a projecting state while the operation unit is receiving a pressing operation performed by the operator, wherein the projector is in a non-projecting state while the operation unit is not receiving a pressing operation performed by the operator, wherein the controller controlling the operation of the projector sets a priority to each of the wired input receiver and the wireless input receiver, and in response to receiving as input a video signal into an input receiver having a higher priority, does not determine whether a video signal is input into an input receiver having a lower priority, and causes the projector to project the video signal input into the input receiver having the higher priority, characterized in that the priority can be set by the operator of the image projection device, wherein the main body housing the projector is provided with a button for the operator to perform an operation to set the priority, wherein the projector is in the projecting state while the operator is pressing the operation unit, wherein a priority setting screen for the operator to set the priority is displayed on the projection image output by the projector, and wherein while the priority setting screen is open, projection is performed without a pressing operation on the operation unit. a projector configured to project an image, and a main body housing the projector, an operation unit configured to receive an operation performed by an operator, a controller configured to control an operation of the projector, and a switching unit configured to switch whether to supply power from the controller to the projector in response to a pressing operation on the operation unit, a wired input receiver configured to receive as input a video by wire, and a wireless input receiver configured to receive as input a video by radio, wherein the projector is in a projecting state while the operation unit is receiving a pressing operation performed by the operator, wherein the projector is in a non-projecting state while the operation unit is not receiving a pressing operation performed by the operator, wherein the controller controlling the operation of the projector sets a priority to each of the wired input receiver and the wireless input receiver, and in response to receiving as input a video signal into an input receiver having a higher priority, does not determine whether a video signal is input into an input receiver having a lower priority, and causes the projector to project the video signal input into the input receiver having the higher priority, characterized in that the priority can be set by the operator of the image projection device, wherein the main body housing the projector is provided with a button for the operator to perform an operation to set the priority, wherein the projector is in the projecting state while the operator is pressing the operation unit, wherein a priority setting screen for the operator to set the priority is displayed on the projection image output by the projector, and wherein while the priority setting screen is open, projection is performed without a pressing operation on the operation unit.