Assuming that patent trolls would come up in the field of software and the like in Japan in the future, we have proposed countermeasures to apply compulsory license against their exercise of patent right. Specifically, in order to avoid injunctive relief of the patent trolls, we have proposed that the enforcement regulation for Japanese Patent Act Article 83 is overhauled in attempt to broadly construe the provision of “the grant of non-exclusive license where invention is not worked” as “the grant of non-exclusive license where invention will not be worked in the future”. Also, we have compared such countermeasures with other countermeasures to apply the principle of abuse of rights to the injunctive relief.