An apparatus for measuring permittivity of a sample. The apparatus includes: a sample chamber including a sealed space portion in which a sample to be measured is put; a pressure adjusting unit for varying pressure by applying water pressure to the space portion of the sample chamber; a permittivity sensor for measuring permittivity of the sample and disposed outside the sample chamber; measurement conducting wires including conductors, installed to contact the sample and connected to the permittivity sensor by using electric wires; and a data logger for storing data relating to permittivity that is measured by the permittivity sensor.