Microchip

A microchip comprising:

• a first substrate and a second substrate, said first substrate being superposed on said second substrate and having a surface with a groove;
• and
• a fluid circuit composed of a cavity defined by said groove and a surface on said first substrate side of said second substrate, wherein
• said fluid circuit includes a fluid retaining reservoir for retaining a fluid,
• said fluid retaining reservoir includes:
• a fluid outlet for allowing said fluid to flow out from said fluid retaining reservoir;
• and
• a partition dividing said fluid retaining reservoir into a first region where said fluid is introduced and a second region where said fluid outlet is included,
• said partition includes a communication gate for allowing communication between said first region and said second region, and
• at least a part of said partition includes a curved portion formed of a wall in a shape of a curve as seen from a surface of said microchip.