A living body phantom according to the present invention, which is used as a testing sample in a prepared slide in estimating the performance of a microscope objective lens with the image of the testing sample in the prepared slide acquired by an imaging means via the microscope objective lens and with optical characteristics obtained from the image of the testing sample, includes a non-gel-like solution at least including: a solvent which at least includes water, a refractive index adjustment agent, and a scattering body or which at least includes a refractive index adjustment agent and a scattering body and a thickener.
