A video output apparatus comprising: an operation device (120 200) configured to output an operation signal indicating a code according to an operation performed by a user; an operation signal processor configured to execute a process according to the operation signal upon receipt of the operation signal; and a storage configured to store a plurality of programs, for achieving a plurality of functions, and setting data comprising an association between codes indicated by operation signals and any of the plurality of programs, wherein the operation device (120 200) includes a definition operation part configured for allocation to one function which is selected by the user among the plurality of functions achieved by any of the plurality of programs, the plurality of functions includes functions each configured to require a multi-step operation to the operation device by the user for execution, and, characterized in that, the plurality of programs includes a function allocation setting program for outputting an operation image to a display device (150 210B), the operation image configured to provide, to the user, setting for allocating the one function of the plurality of functions to the definition operation part, and, the storage comprises in the setting data an initial association, said initial association configured to associate the code indicated by the operation signal due to an operation on the definition operation part by the user and the function allocation setting program, and the operation signal processor is configured to execute the function allocation setting program, when the video output apparatus is in an initial state, based on the initial association and outputs the operation image to the display device, upon receipt of the operation signal output from the operation device (120 200) due to a single operation on the definition operation part by the user, the initial state being continued until the one function is allocated to the definition operation part by the user, and the operation signal processor is configured to execute the one function, after the one function is allocated to the definition operation part, upon receipt of the operation signal output from the operation device (120 200) due to the single operation on the definition operation part by the user. an operation device (120 200) configured to output an operation signal indicating a code according to an operation performed by a user; an operation signal processor configured to execute a process according to the operation signal upon receipt of the operation signal; and a storage configured to store a plurality of programs, for achieving a plurality of functions, and setting data comprising an association between codes indicated by operation signals and any of the plurality of programs, wherein the operation device (120 200) includes a definition operation part configured for allocation to one function which is selected by the user among the plurality of functions achieved by any of the plurality of programs, the plurality of functions includes functions each configured to require a multi-step operation to the operation device by the user for execution, and, characterized in that, the plurality of programs includes a function allocation setting program for outputting an operation image to a display device (150 210B), the operation image configured to provide, to the user, setting for allocating the one function of the plurality of functions to the definition operation part, and, the storage comprises in the setting data an initial association, said initial association configured to associate the code indicated by the operation signal due to an operation on the definition operation part by the user and the function allocation setting program, and the operation signal processor is configured to execute the function allocation setting program, when the video output apparatus is in an initial state, based on the initial association and outputs the operation image to the display device, upon receipt of the operation signal output from the operation device (120 200) due to a single operation on the definition operation part by the user, the initial state being continued until the one function is allocated to the definition operation part by the user, and the operation signal processor is configured to execute the one function, after the one function is allocated to the definition operation part, upon receipt of the operation signal output from the operation device (120 200) due to the single operation on the definition operation part by the user.