While deterioration in processing efficiency caused by printing devices with slow printing speed is suppressed, facilities necessary to manufacture can bodies are able to be shared. A can body manufacturing system includes: a can body conveyance route, by which can bodies are conveyed, provided to branch halfway and thereafter merge again, the can body conveyance route at least including a first branching conveyance route and a second branching conveyance route; a first printing device performing printing on can bodies conveyed by the first branching conveyance route; and a second printing device performing printing on can bodies conveyed by the second branching conveyance route, the number of can bodies on which printing is performed by the second printing device per unit time being different from the number of can bodies on which printing is performed by the first printing device per unit time.