A coil spring manufacturing method of a vehicle suspension member, the member comprising: a coating bath in which a powder coat (P) is filled; a circulator which flows the powder coat (P) to form a fluidized bed ; a relative movement mechanism which supports the coating bath ; and a conveyor which conveys a coil spring (S) to the coating bath , the method being characterized in that while the coil spring (S) is immersed in the fluidized bed in which the powder coat (P) flows for coating, the fluidized bed includes an vertical stream area including an upstream area in which the powder coat (P) flows from a lower side to an upper side and a downstream area in which the powder coat (P) flows from the upper side to a lower side, the upstream area being formed at a center part of the fluidized bed , the downstream area being formed at an outer peripheral part of the fluidized bed , the powder coat (P) flowing upstream from the upstream area moves from the center part toward the outer peripheral part of the fluidized bed , on a surface side of the fluidized bed , and the powder coat (P) flowing downstream from the downstream area moves from the outer peripheral part toward the center part of the fluidized bed , on a bottom side of the fluidized bed , and the coil spring (S) is immersed in the upstream area of the vertical stream area , which is formed at the center part of the fluidized bed , while an end coil of the coil spring (S) faces upward, and the coil spring (S) is periodically subjected to a relative movement with respect to a direction containing components vertical to a central axis (X) of the coil spring (S), to transversely cross the upstream area . a coating bath in which a powder coat (P) is filled; a circulator which flows the powder coat (P) to form a fluidized bed ; a relative movement mechanism which supports the coating bath ; and a conveyor which conveys a coil spring (S) to the coating bath , the method being characterized in that while the coil spring (S) is immersed in the fluidized bed in which the powder coat (P) flows for coating, the fluidized bed includes an vertical stream area including an upstream area in which the powder coat (P) flows from a lower side to an upper side and a downstream area in which the powder coat (P) flows from the upper side to a lower side, the upstream area being formed at a center part of the fluidized bed , the downstream area being formed at an outer peripheral part of the fluidized bed , the powder coat (P) flowing upstream from the upstream area moves from the center part toward the outer peripheral part of the fluidized bed , on a surface side of the fluidized bed , and the powder coat (P) flowing downstream from the downstream area moves from the outer peripheral part toward the center part of the fluidized bed , on a bottom side of the fluidized bed , and the coil spring (S) is immersed in the upstream area of the vertical stream area , which is formed at the center part of the fluidized bed , while an end coil of the coil spring (S) faces upward, and the coil spring (S) is periodically subjected to a relative movement with respect to a direction containing components vertical to a central axis (X) of the coil spring (S), to transversely cross the upstream area . <EOS>