1. An embroidery data generator configured to generate embroidery data comprising: a pattern storing unit configured to store plural types of pattern data configured for sewing one or more sub-patterns according to a predetermined stitch pattern, the one or more sub-patterns constituting an embroidery pattern; and a control device configured to: randomly extract pattern data configured for sewing the one or more sub-patterns from the plural types of pattern data stored in the pattern storing unit, and assign extracted pattern data to the one or more sub-patterns.