A carbon nanomaterial production apparatus comprising: a reaction tube 2 into which raw material gas and carrier gas are supplied and accordingly in which carbon nanomaterial is grown; a connection tube 4 that is connected to the reaction tube 2 and through which an aerosol-like mixture of the carbon nanomaterial and the carrier gas passes; and a collection tube 3 that is connected to the connection tube 4 and collects the carbon nanomaterial from the mixture, wherein the collection tube 3 includes: a discharge section 32 that is located above a junction 33 with the connection tube 4 and discharges the carrier gas contained in the mixture to outside, and a trapping section 31 that is located below the junction 33 with the connection tube 4 and configured to trap the carbon nanomaterial that is separated from the mixture by gravitational sedimentation and falls downward while the carrier gas flows upward, the reaction tube 2 further includes a main reaction section 21 that has catalyst carriers inside and in which the carbon nanomaterial around the catalyst carriers is grown and the carbon nanomaterial is peeled from the catalyst carriers by agitation of the catalyst carriers with the carrier gas, and a separation section 22 that is located above the main reaction section 21 configured to separate the catalyst carriers falling without being accompanied by the carrier gas and the carbon nanomaterial thus peeled being accompanied by the carrier gas, wherein a cross-sectional area of the separation section 22 is larger than a cross-sectional area of the main reaction section 21, an introduction section 23 that is positioned above the separation section 22 and serves as a junction with the connection tube 4, wherein in the reaction tube 2 an end portion of the separation section 22 near the main reaction section 21 is in a tapered shape such that its cross-sectional area becomes smaller as it comes closer to the main reaction section 21, and an end portion thereof near the introduction section 23 is in a tapered shape such that its cross-sectional area becomes smaller as it comes closer to the introduction, and wherein the connection tube 4 inclines so that the mixture flows falling from the reaction tube 2 toward the collection tube 3. a reaction tube 2 into which raw material gas and carrier gas are supplied and accordingly in which carbon nanomaterial is grown; a connection tube 4 that is connected to the reaction tube 2 and through which an aerosol-like mixture of the carbon nanomaterial and the carrier gas passes; and a collection tube 3 that is connected to the connection tube 4 and collects the carbon nanomaterial from the mixture, wherein the collection tube 3 includes: a discharge section 32 that is located above a junction 33 with the connection tube 4 and discharges the carrier gas contained in the mixture to outside, and a trapping section 31 that is located below the junction 33 with the connection tube 4 and configured to trap the carbon nanomaterial that is separated from the mixture by gravitational sedimentation and falls downward while the carrier gas flows upward, a discharge section 32 that is located above a junction 33 with the connection tube 4 and discharges the carrier gas contained in the mixture to outside, and a trapping section 31 that is located below the junction 33 with the connection tube 4 and configured to trap the carbon nanomaterial that is separated from the mixture by gravitational sedimentation and falls downward while the carrier gas flows upward, the reaction tube 2 further includes a main reaction section 21 that has catalyst carriers inside and in which the carbon nanomaterial around the catalyst carriers is grown and the carbon nanomaterial is peeled from the catalyst carriers by agitation of the catalyst carriers with the carrier gas, and a separation section 22 that is located above the main reaction section 21 configured to separate the catalyst carriers falling without being accompanied by the carrier gas and the carbon nanomaterial thus peeled being accompanied by the carrier gas, a main reaction section 21 that has catalyst carriers inside and in which the carbon nanomaterial around the catalyst carriers is grown and the carbon nanomaterial is peeled from the catalyst carriers by agitation of the catalyst carriers with the carrier gas, and a separation section 22 that is located above the main reaction section 21 configured to separate the catalyst carriers falling without being accompanied by the carrier gas and the carbon nanomaterial thus peeled being accompanied by the carrier gas, wherein a cross-sectional area of the separation section 22 is larger than a cross-sectional area of the main reaction section 21, an introduction section 23 that is positioned above the separation section 22 and serves as a junction with the connection tube 4, wherein in the reaction tube 2 an end portion of the separation section 22 near the main reaction section 21 is in a tapered shape such that its cross-sectional area becomes smaller as it comes closer to the main reaction section 21, and an end portion thereof near the introduction section 23 is in a tapered shape such that its cross-sectional area becomes smaller as it comes closer to the introduction, and wherein the connection tube 4 inclines so that the mixture flows falling from the reaction tube 2 toward the collection tube 3.