A digital ink coding method includes: a coordinate coding step of acquiring a first binary data indicating a series of sets of x coordinate data and y coordinate data by coding N pieces of position data, each including a set of x coordinate data and y coordinate data acquired in connection with a motion of a pointing device during a period determined by a state of the pointing device; a width coding step of acquiring a second binary data defining widths at positions indicated by N pieces of position data by coding M pieces of width data, where M is an integer equal to or greater than 1 and equal to or smaller than N and the second binary data is separated from the first binary data; and a serialization step of generating a binary stream including the first binary data and the second binary data in mutually different regions.