A method for analyzing a sample in a liquid is provided, which is suitable for easily and reliably preventing a liquid for analysis from being evaporated. When the sample in the liquid is observed by using a scanning probe microscope (SPM), a sealing liquid (17) immiscible with a liquid for analysis (16) is filled around the liquid for analysis (16), in which a sample (13) and a probe (15) are immersed, so as to form a sealing state, in which the liquid for analysis (16) is isolated from an external gas. The SPM enables the probe (15) disposed on a front end of a cantilever (14) to approach a surface of the sample (13) immersed in the liquid, scans the surface of the sample, and detects an interaction between the sample (13) and the probe (15), thereby generating an image.