A microchip comprising: a resinous base formed by injection molding and having cylindrical parts protruding from one surface of a substrate, with a plurality of fine channels formed on the other surface of the substrate, and a through-hole which penetrates each cylindrical part along an axis of the cylindrical part in such a way that a diameter of an inner wall of the through-hole gradually decreases from a tip end of the cylindrical part to a fine channel of the plurality of fine channels at a first inclination angle in the penetration direction of the through-hole, and which communicates with the fine channel; and a resinous covering member bonded to the other surface of the resinous substrate on which the fine channels are formed, wherein the microchip is configured to introduce a liquid sample from the tip end of the cylindrical part through the through-hole; wherein a wall thickness of the cylindrical part on a tip end side of the cylindrical part to be supplied with a liquid sample is made smaller than a wall thickness on a substrate side of the cylindrical part on which the cylindrical part is formed; wherein the cylindrical part is formed in an approximate truncated cone shape wherein a diameter of an outer wall of the cylindrical part is gradually increased at a second inclination angle from the tip end of the cylindrical part toward the other surface; the outer wall of the cylindrical part is formed in such a way that the second inclination angle in the penetration direction of the through-hole is greater than 0 degree without exceeding 5 degrees; and an inner wall of the cylindrical part is formed in such a way that an absolute value of the first inclination angle is greater than that of the second inclination angle; and wherein an interval between two through-holes is 1.1 times or more without exceeding 5 times the maximum diameter of two mutually adjacent through-holes. a resinous base formed by injection molding and having cylindrical parts protruding from one surface of a substrate, with a plurality of fine channels formed on the other surface of the substrate, and a through-hole which penetrates each cylindrical part along an axis of the cylindrical part in such a way that a diameter of an inner wall of the through-hole gradually decreases from a tip end of the cylindrical part to a fine channel of the plurality of fine channels at a first inclination angle in the penetration direction of the through-hole, and which communicates with the fine channel; and a resinous covering member bonded to the other surface of the resinous substrate on which the fine channels are formed, wherein the microchip is configured to introduce a liquid sample from the tip end of the cylindrical part through the through-hole; wherein a wall thickness of the cylindrical part on a tip end side of the cylindrical part to be supplied with a liquid sample is made smaller than a wall thickness on a substrate side of the cylindrical part on which the cylindrical part is formed; wherein the cylindrical part is formed in an approximate truncated cone shape wherein a diameter of an outer wall of the cylindrical part is gradually increased at a second inclination angle from the tip end of the cylindrical part toward the other surface; the outer wall of the cylindrical part is formed in such a way that the second inclination angle in the penetration direction of the through-hole is greater than 0 degree without exceeding 5 degrees; and an inner wall of the cylindrical part is formed in such a way that an absolute value of the first inclination angle is greater than that of the second inclination angle; and wherein an interval between two through-holes is 1.1 times or more without exceeding 5 times the maximum diameter of two mutually adjacent through-holes.