A charged-particle beam lithography system is provided. A region to be patterned is divided into plural frames, a main deflection positions a beam to a subfield within the frame, and an auxiliary deflection draws a pattern in units of subfield. The deflection control portion draws a pattern in units of stripe including a first frame drawing region and a second frame drawing region. The first frame drawing region corresponds to one of the frames, and the second frame drawing region is a region moved by a distance C from the first frame drawing region toward a frame to be drawn next. The deflection control portion controls the driver to alternately pattern a first sub-field drawing region in the first frame drawing region and a second sub-field drawing region in the second frame drawing region. The distance C satisfies 0