The endoscope apparatus includes a heat exchanger, a first tube, and a second tube. The front-end portion is cooled down by repeating alternately, the other operation which is opposite an one operation, which is an operation of generating a flow of the cooling liquid from the other end of the first tube to the one end of the first tube, and a flow of the cooling liquid from the one end of the second tube to the other end of the second tube, and the one operation which is an operation of generating a flow of the cooling liquid from the other end of the second tube to the one end of the second tube, and a flow of the cooling liquid from the one end of the first tube to the other end of the first tube.