A cart is provided for mounting a portable ultrasonic diagnostic device, the cart being small in size and having high operability, and the portable ultrasonic diagnostic device is opened and used in the state of being kept mounted on the cart. The cart has a top board 1 for placing the portable ultrasonic diagnostic device thereon, a support column 2 for supporting the top board in such a manner as movable up and down, multiple legs 3 for supporting the support column, wheels 4 respectively attached to the legs, and a unit 5 having a predetermined function. The unit 5 is placed below the top board 1 in the rear of the support column 2, and the center of gravity of the cart is positioned in the rear of the center of the support column 2. This cart has a simple configuration enabling downsizing, and it is high in operability. It is possible to open and use the portable ultrasonic diagnostic device in the state that the portable ultrasonic diagnostic device is kept mounted on the cart.