There is provided solution testing equipment which can detect an output variation of a THz oscillation device using a THz wave (hν) by contacting a liquid or cells on an RTD oscillation device, and can reduce the size and weight thereof. The solution testing equipment includes: a THz oscillation device configured to radiate the THz wave Is; a THz detection device configured to receive the THz wave Is; and a solution as a test object disposed on the THz oscillation device, in which the solution is tested on the basis of output characteristics of the terahertz wave varying in response to a relative permittivity of the solution.