Abstract: The present invention relates to an apparatus for determining the presence or absence of a target analyte in a liquid sample, comprising:(i) a container capable of accommodating the liquid sample and having a transparent portion; and(ii) an insertion member which is capable of being inserted into the container comprising;a porous member which has a main surface and a reverse surface and which has on the main surface a substance capable of specifically binding to the target analyte; andan absorbent bonded to the reverse surface of the porous member;the porous member being supported in the insertion member whereby, when the insertion member is inserted into the container, the main surface can be observed from the outside of the container through the transparent portion of the vessel and the liquid sample is absorbed into the absorbent through the porous member.According to the analyzer of the present invention, the presence or absence of a target analyte in a sample can be easily determined.