A microchip 1 in which a resinous film can be inhibited from sagging into a channel. The microchip 1 comprises: a resinous substrate 2 having a channel groove formed therein; and a resinous film bonded to a surface of the substrate on which the channel groove has been formed. A micro-channel 3 including channels 3A and channels 3B is formed by the channel groove and the resinous film 10. The total length of the channels 3B, which is parallel to the X direction for the resinous substrate 2, is larger than the total length of the channels 3A, which is parallel to the Y direction for the resinous substrate 2. The resinous substrate 2 has been bonded to the resinous film so that the sides parallel to the channels 3B are parallel to the TD direction of the resinous film and that the sides parallel to the channels 3A are parallel to the MD direction of the resinous film.