A bulking apparatus includes a hot air generator, an air supply duct having an inlet for receiving hot air and an outlet for delivering hot air to nonwoven fabric, and a sucking part sucking in hot air delivered from the outlet and passed through nonwoven fabric. The air supply duct has an inflow portion leading hot air introduced into the inlet to flow in parallel to the transverse direction of the nonwoven fabric and an outflow portion forming an angle with the inflow portion leading hot air flowing through the inflow portion to the outlet. The air supply duct has a plurality of baffle plates disposed therein, each baffle plate having a flow-facing part and a flow-guiding part located in the inflow and outflow portions, respectively. The baffle plates are arranged such that the inflow path in the inflow portion has a decreasing cross-sectional area with distance from the inlet.
