Analyzing device

An analytical device comprising a test piece in a hollow casing made of a moisture-impervious material, said test piece being made of a dry porous material in which a sample is freely mobile in the wet state, wherein a specific binding substance is immobilized at a detection site on the dry porous material stably even when in the wet state, and another specific binding substance labeled directly with a signal-generating substance is retained at a site physically distant from said detection site in such a manner that the labeled specific binding substance is mobile in the wet state, whereby a sample first contacts with said specific binding substance immobilized on said porous material to form a first complex between an analyte in the sample and said specific binding substance, and said directly labeled specific binding substance is then wetted and reaches said detection site to bind to said first complex, said device being adapted in such a manner that the extent of the binding can be observed, and wherein said device is adapted in such a manner that a liquid sample first contacts with said specific binding substance stably immobilized at said detection site on said porous material, indirectly through a sample-receiving dry porous member.