Provided is a cellulose nanofiber carbon for which the specific surface area can be increased and a method for manufacturing the same. This method for manufacturing a cellulose nanofiber carbon thermally treats a cellulose nanofiber to carbonize the same and involves: a freezing step S2 of freezing a solution or gel that includes the cellulose nanofiber to obtain a frozen body; a drying step S3 of drying the frozen body in a vacuum to obtain a dried body; and a carbonizing step S4 of heating and carbonizing the dried body in an atmosphere that does not cause the dried body to combust in order to obtain the cellulose nanofiber carbon.