There is provided a pattern generator that generates a test pattern for performing a scan test for an electronic device. The pattern generator includes: a main memory that stores a scan pattern data block including pattern data for performing the scan test and a scan sequence data block including an instruction indicative of a sequence by which data in the scan pattern data block should be supplied to the electronic device, in association with each other; and a data expanding section that executes the instruction in the scan sequence data block to expand the pattern data in the corresponding scan pattern data block and generate the test pattern.