An apparatus capable of connecting a connector of ultrasonic probe includes a connected part, a wall part and a vent hole. The connected part is provided in a housing and is configured to be capable of connecting a connector of ultrasonic probe. The wall part is provided in a location to surround side faces of the connector in a state of being connected to the connected part. The vent hole is provided between the connected part and the wall part so as to pass through from outside to inside of the housing.