Abstract: Disclosed is a method of bonding upper and lower substrates for manufacturing a plastic micro chip comprising the upper substrate, the lower substrate and a sample filling space having a predetermined height for filling a sample between the upper and lower substrates. According to the method, the upper and lower substrates are bonded by introducing an organic solvent between the upper and lower substrates. In addition, the invention provides a method of manufacturing a micro chip using the method and a micro chip manufactured according to the method. According to the invention, it is possible to easily and precisely bond the upper and lower substrates of the plastic micro chip.