A scroll machining method for forming a wall part (21) configured in a scroll shape on a surface of a workpiece (W), which includes a first scroll machining step of machining one of the wall surfaces (22, 23), in which a tool (14) is moved relative to the workpiece from an outside of the workpiece (W) toward a center part (25) along a predetermined path (L1) while turning the rotary table (17) in a first direction (R1); and a second scroll machining step of machining the other of the wall surfaces (22, 23), in which the tool (14) is moved relative to the workpiece from the center part (25) of the workpiece (W) toward the outside by returning along the predetermined path (L1) while turning the rotary table (17) in a second direction (R2) opposite to the first direction (R1).