In a method for manufacturing carbon fibers by means of a thermal CVD method through catalysts, the method capable of obtaining a uniform film thickness regardless of a growth position and a growth area on a substrate is provided. The substrate on which a catalyst layer is formed is disposed in a reaction container. An atmosphere in the reaction container is set to be a reduced pressure atmosphere including a carbon containing gas having a partial pressure of 10 Pa or less, and the substrate is heated in the atmosphere to grow carbon fibers on the catalyst layer.