Disclosed is an ultrasound diagnosis device for creating an ultrasound image with a high contrast-to-tissue ratio. Said device sends a transmission pulse to the subject, uses an ultrasound probe to receive echoes reflected from an ultrasound contrast agent injected into the subject, and forms an image. The transmission pulse is sent such that nonlinear interactions between the constituent frequency components of said transmission pulse, as a result of the acoustic nonlinearity of the subject, do not produce sum and difference components in the frequency sensitivity range of the ultrasonic probe as the transmission pulse propagates across the subject.