A method of manufacturing an electron-emitting source includes first to third steps. In the first step, a cathode structure made of a metal containing any one of ion, nickel, cobalt, and chromium is heated to a first temperature in a reaction furnace to which a carbon source gas has been introduced, to form a plurality of first carbon nanotubes on the cathode structure by chemical vapor deposition. In the second step, the metal serving as a material of the cathode structure is deposited on at least either one of the cathode structure and the plurality of first carbon nanotubes, to form a catalyst metal layer. In the third step, the cathode structure including the catalyst metal layer is heated to a second temperature higher than the first temperature in the reaction furnace to which the carbon source gas has been introduced, to form a plurality of second carbon nanotubes which are thinner than the first carbon nanotubes on the catalyst metal layer by chemical vapor deposition. An electron-emitting source is also disclosed.