According to one embodiment, an ultrasound diagnosis apparatus includes an ultrasound probe that transmits/receives ultrasound waves to/from a subject, a reference position member arranged on the ultrasound probe, and a sensor located in a position having a predetermined positional relationship relative to a puncture needle. The ultrasound diagnosis apparatus further includes a position information acquisition unit, a needle length information acquisition unit, and a display. The position information acquisition unit acquires position information of the reference position member and the sensor. The needle length information acquisition unit acquires needle length information indicating the length of the puncture needle based on the position information of the reference position member and the sensor when the tip of the puncture needle is in contact with the reference position member, and the relative position. The display displays information to guide a puncture by the puncture needle based on the needle length information.