Provided is a liquid sample analyzing method for analyzing an analyte in a liquid sample by using a test piece (1) on which overflow blocking lines (7) are formed to prevent the liquid sample from flowing to the outside from a passage region (3a) of an extended layer (3). In a state in which the liquid sample is not extended in the passage region (3a) of the extended region (3), the test piece (1) is measured so as to cross the passage region (3a) of the extended layer (3) and the overflow blocking lines (7). Thus in a state in which a difference in brightness is large between the passage region (3a) of the extended region (3) and the overflow blocking lines (7), it is possible to properly recognize the boundary portions between the passage region (3a) of the extended region (3) and the overflow blocking lines (7).