Abstract: The present invention is an analytical device which comprises a porous piece assembly consisting of a liquid reagent-receiving porous piece (1), a labeled substance-retaining piece (2), a test piece (3) comprising a detection site (4) and a reference site (5), and a sample-absorbing porous material piece (6); and a sample-receiving porous material piece (7) disposed independently therefrom and partially communicated therewith through a connection. The analytical device of the present invention exhibits extremely high sensitivity and can accurately perform various types of analysis.