An offline teaching device includes: a storage unit that stores a program; a display control unit that causes a monitor to display four or more coordinate points P1 to P6 based on teaching point data described in the program and one line connecting the four or more coordinate points P1 to P6 successively; and a correction amount generation unit that, after two coordinate points P2 and P5 are selected on the monitor from remaining coordinate points P2 to P5 except the coordinate points P1 and P6 serving as a starting point and an ending point of the line and one coordinate system is selected among a plurality of coordinate systems, generates correction amounts of the coordinate points P2 to P5 without changing the teaching point data on the basis of dragging of a segment between the selected two coordinate points P2 and P5 according to the selected coordinate system.