The object of the invention is an ultrasound device for forming skeleton density information. This ultrasound device comprises for forming skeleton density information at least two transmitters 100, 102 having a distance of L1 between them for transmitting ultrasound signals into the skeleton, at least two receivers 104 having a distance of L2 between them for receiving ultrasound signals from the skeleton, as the calibrated known distance L is at least one of distances L1 and L2. The ultrasound device comprise also processing unit 101 for calculating a ultrasound velocity in the skeleton for forming skeleton density information on the basis of the ultrasound signals received by said receivers 104, 106 by dividing known distance by an average of a travel time difference for a ultrasound signal between the receivers 104, 106 receiving said ultrasound signal from the first transmitter 100 and a travel time difference for a ultrasound signal between the receivers receiving said ultrasound signal from the second transmitter 102.
