A holding device, disposed in a bio-detecting instrument having a plurality of sensing terminals, for holding a test strip, the holding device comprising: a first casing; a second casing, assembled with the first casing to form an accommodating space there between, wherein the sensing terminals are extended into the accommodating space, and the test strip is configured to be delivered into the accommodating space through a first opening and contact with the sensing terminals; an ejecting member, comprising a push rod and a first stopper, wherein the push rod is configured to be reciprocated in the accommodating space through a second opening; and an elastic member, disposed between the second casing and the first stopper, wherein the elastic member is configured to be compressed by driving the ejecting member to an ejecting position, where the push rod enters the accommodating space and is adapted to push the test strip outward without being contact with the sensing terminals, and the elastic member is configured to be released by drawing the push rod back from the accommodating space to an initial position, wherein the first casing is provided with a first guiding groove having an inner profile matched with an outer profile of the push rod, so as to guide the push rod sliding in the accommodating space, wherein the first casing is provided with further a second guiding groove connected to the first guiding groove, and the first stopper is configured to slide along the second guiding groove, wherein the ejecting member further comprises a second stopper and an intermediate connecting rod located between the first stopper and the second stopper, and the intermediate connecting rod is located in the second guiding groove when the ejecting member is driven to the ejecting position, the holding device being characterized in that the first casing is provided with a notch, for restricting strokes of the first stopper and the second stopper and that the first stopper and the second stopper are located at two opposite sides of the notch, respectively. a first casing; a second casing, assembled with the first casing to form an accommodating space there between, wherein the sensing terminals are extended into the accommodating space, and the test strip is configured to be delivered into the accommodating space through a first opening and contact with the sensing terminals; an ejecting member, comprising a push rod and a first stopper, wherein the push rod is configured to be reciprocated in the accommodating space through a second opening; and an elastic member, disposed between the second casing and the first stopper, wherein the elastic member is configured to be compressed by driving the ejecting member to an ejecting position, where the push rod enters the accommodating space and is adapted to push the test strip outward without being contact with the sensing terminals, and the elastic member is configured to be released by drawing the push rod back from the accommodating space to an initial position, wherein the first casing is provided with a first guiding groove having an inner profile matched with an outer profile of the push rod, so as to guide the push rod sliding in the accommodating space, wherein the first casing is provided with further a second guiding groove connected to the first guiding groove, and the first stopper is configured to slide along the second guiding groove, wherein the ejecting member further comprises a second stopper and an intermediate connecting rod located between the first stopper and the second stopper, and the intermediate connecting rod is located in the second guiding groove when the ejecting member is driven to the ejecting position, the holding device being characterized in that the first casing is provided with a notch, for restricting strokes of the first stopper and the second stopper and that the first stopper and the second stopper are located at two opposite sides of the notch, respectively.