An endoscope includes an insertion section configured to be inserted into a subject, a distal end portion disposed at a distal end of the insertion section, the distal end portion including an observing section configured to observe the subject, a holding section configured to hold the observing section, a heat medium that changes in phase from liquid to gas when exceeding a predetermined temperature, and a heat receiving chamber configured to house the heat medium, and a heat radiation chamber communicating with the heat receiving chamber, the heat medium gasified in the heat receiving chamber being capable of entering the heat radiation chamber.
