portable ultrasonic diagnostic apparatus of the present invention comprises a housing having a substrate inside , a battery for supplying electric power to the substrate is housed in the battery housing part which is provided in said housing, said provided in the battery accommodating portion, the battery or the substrate are heated in generated heat by said battery or said substrate an intake opening for the intake air of the surrounding, and the flow path for guiding the air surrounding the battery or the substrate is sucked from the intake opening, the periphery of the battery or the substrate has passed through the flow path of I and an exhaust opening for exhausting air.本発明の携帯型超音波診断装置は、基板を内部に有する筺体と、前記筺体内に設けられるバッテリ収容部に収容され前記基板に電力を供給するバッテリと、前記バッテリ収容部に設けられ、前記バッテリ又は前記基板によって発生された熱で加熱された前記バッテリ又は前記基板の周囲の空気を吸気する吸気用開口部と、前記吸気用開口部から吸気された前記バッテリ又は前記基板の周囲の空気を導く流路と、前記流路を通過した前記バッテリ又は前記基板の周囲の空気を排気する排気用開口部とを備える。
