The present invention addresses the problem of providing a novel compound that has an antagonistic activity against
thyroid-stimulating
hormone receptors and is useful for the treatment of
thyroid-related diseases. The present invention relates to a di-substituted bicyclo[1.1.1]
pentane compound represented by formula (I) or a pharmacologically acceptable salt thereof. The compound or the pharmacologically acceptable salt thereof according to the present invention has an antagonistic activity against
thyroid-stimulating
hormone receptors and is useful as, for example, a therapeutic agent for thyroid-related diseases (e.g., hyperthyroidism, Graves'
disease, thyroid
eye disease, and
thyroid cancer).