A blood test apparatus has a housing with an opening, and a plunger that moves back and forth inside the housing, the plunger having a projecting member. A fixing member fixes the plunger, which is provided in the housing. A blood sampling cartridge, in which a blood sensor, a puncturer, and a holder that holds the blood sensor and the puncturer, are integrated. The blood sampling cartridge is removably attached to the opening. The puncturer includes a lancet, one end of which is held by the plunger, and a blood collection needle attached to an other end of the lancet. A measuring circuit measures a signal obtained from the blood sensor to analyze components in the blood.