A permeability evaluation method for evaluating permeability of heavy metal ions through a specimen, comprising a step of, in a state in which a first liquid containing heavy metal ions and a second liquid containing water and an organic solvent are separated by a specimen, applying a voltage between a positive electrode provided on the side of the first liquid and a negative electrode provided on the side of the second liquid and measuring the value of the current flowing between the positive electrode and the negative electrode, wherein the specimen contains an insulating material used in semiconductor production, and the heavy metal ion concentration of the first liquid is 0.5 mg/kg or more.