An apparatus for supporting parallelization according to the invention is characterized by comprising a serialization unit for converting a first concurrent program having a concurrent structure into a sequential program capable of being sequentially executed, a debugging unit for debugging the sequential program and forming debugging information, and a concurrent program programming unit for performing parallelization of the debugged sequential program on the basis of the debugging information to convert the sequential program into a second concurrent program. With above configuration, the debugging unit includes a unit for introducing information associated with concurrency to the sequential program.