A lancet device is provided. The lancet device includes a cover and a case body. The cover includes a first guidance element and a first fastener. The case body includes a second guidance element and a second fastener. The first guidance element and the second guidance element could be a differential recognition to point out the moving direction of install or uninstall with the lancet device. The first fastener and the second fastener could move relatively with the moving direction description above, and then a connecting state of the cover and the case body is changed through carried out the unitary fastening movement.一種採血裝置,其包括一蓋體與一殼體。蓋體包括一第一導引部與一第一卡扣部。殼體包括一第二導引部與一第二卡扣部。第一導引部與第二導引部能產生一差異性辨識指引採血裝置的裝卸作動方向。第一卡扣部與第二卡扣部能依循上述導引作動方向產生一相對運動,藉以完成單次卡扣作動改變蓋體與殼體間的接合狀態。
