According to one embodiment, a detector detects a position at a leading end of a puncture needle. A determination unit determines a first scanning region in a subject and a second scanning region based on the position at the detected leading end, the second scanning region being narrower than the first scanning region. A transmission/reception controller controls a transmitter and a receiver to switches between first ultrasonic scanning for the first scanning region and second ultrasonic scanning for the second scanning region according to an instruction from an operator.