A vaporizer is provided with a vaporizing chamber heated by heaters; a primary filter positioned in a bottom end portion of the vaporizing chamber and heated by the heater; a liquid material supply portion for dropping down a flow-controlled liquid material from upper portion of the vaporizing chamber toward the primary filter; a carrier gas guiding passage for guiding a carrier gas into the underside of the primary filter; and a material delivering passage for discharging a mixed gas including the carrier gas and a vaporized liquid material from the top of the vaporizing chamber. The liquid material dropped down onto the primary filter is partially vaporized, while the rest thereof is atomized by being subjected to bubbling effect provided by the carrier gas flowing from underneath.