Abstract: The present invention relates to a method for manufacturing a microvalve device of a lab-on-a-chip by interposing a polyvinylidene chloride film between upper and lower substrates, each of which is produced by injection molding of a rigid polymer resin, and heating and pressurizing the resultant structure. The present invention also relates to a microvalve device manufactured by the method. According to the method of the present invention, each of the upper and lower substrates can be produced by injection molding of a rigid polymeric material, thus being appropriate for mass production in a short time. Excellent thermal bonding properties between the polyvinylidene chloride film and the substrates enable the formation of the rigid substrate/film membrane/rigid substrate structure in an easy and reliable manner, which shortens the time required to manufacture the microvalve device. Therefore, the method of the present invention is suitable for the mass production of labs-on-a-chip.