A blood clotting time measurement cartridge that can keep an amount of blood constant while simplifying a configuration and easing a blood injection operation, and a blood clotting time measuring device using the cartridge. The cartridge includes a measurement flow channel wherein blood is housed and transmission of light detects whether there is blood in a predetermined position, an introduction opening on one end side of the channel from which blood is introduced, a communication opening on the other end through which it is possible to cause, by suction or pressurization of air or blood introduced from the introduction opening, the blood in the channel to make a reciprocating motion so as to pass through the predetermined position, a partition wall that partitions a blood injection space connected to the introduction opening, and an absorption member on an outer side of the partition wall that absorbs blood beyond the wall.