An embodiment of the present invention provides a microfluidic device into which fluid can be more easily introduced. A microfluidic device (1) is configured such that: (i) an upper substrate (2) is bonded to a lower substrate (6) via a sealing pattern (5) in such a manner that at least a portion of an edge of the upper substrate (2) is located inward of an edge of the lower substrate (6); and (ii) the sealing pattern (5) includes at least one gap (12) that is provided at a position where the edge of the upper substrate (2) is located inward of the edge of the lower substrate (6).