Sample isolation particle, sample isolation device and sample isolation method

The present invention solves the antagonistic relationship between the buoyancy of a sample isolation particle and the dispersibility/stability of the sample isolation particle when a target substance is isolated using the buoyancy of the sample isolation particle. A particle complex is used for the isolation of the sample in a liquid, the particle complex being provided with: a first particle on the surface of which trapping molecules for trapping the sample are bound and which has a first specific gravity; a second particle having a second specific gravity that is larger than the first specific gravity; and a connecting section for connecting the first particle to the second particle and which dissociates under a first condition.