A vapor grown carbon fiber, each fiber filament of the carbonfiber having a branching degree of at least 0.15 occurrences/.mu.m and a bulk density of 0.025 g/cm.sup.3 or less and a producing method of the carbon fiber by spraying a raw material solution containing a carbon source and a transition metallic compound into a reaction zone and subjecting the raw material solution to thermal decomposition, which is characterized in (1) spraying the raw material solution at a spray angle of 3.degree. to 30.degree. and (2) feeding a carrier gas through at least one site other than an inlet through which the raw material solution is sprayed, and a composite material comprising the carbon fiber.