An ink file output method is provided, which includes: generating M (M is an integer of 1 or more) pieces of stroke data SD on the basis of event data generated as M input devices move, respectively; generating N (N is an integer of 1 or more and M or less) kinds of logical names LN (metadata) identifying the M number of input devices; generating a metadata block associating the M pieces of stroke data SD with the N kinds of logical names LN; and writing the M pieces of stroke data SD and the metadata block to an ink file.