1. An ultrasound diagnosis apparatus comprising: a processor connected to a memory, wherein the processor is configured to: calculate a movement distance between a tissue image in a first phase appearing after an ultrasound contrast agent is given to a subject, and a tissue image in a second phase that is a phase later than the first phase; create a corrected image from a contrast enhanced image in the first phase by matching the contrast enhanced image in the first phase in position with a contrast enhanced image in the second phase based on the movement distance; create a composite image by combining the corrected image and the contrast enhanced image in the second phase; and control a display unit to display the composite image, wherein the tissue image in the first phase is an ultrasound image created by separating a fundamental wave corresponding to a transmission frequency of ultrasound waves transmitted from an ultrasound probe onto the subject in the first phase from reflected waves of the ultrasound waves in the first phase, the tissue image in the second phase is an ultrasound image created by separating the fundamental wave corresponding to the transmission frequency of ultrasound waves transmitted from the ultrasound probe onto the subject in the second phase from reflected waves of the ultrasound waves in the second phase, the contrast enhanced image in the first phase is an ultrasound image created by separating a subharmonic wave or a higher harmonic wave of the transmission frequency from the reflected waves used for creating the tissue image in the first phase, and the contrast enhanced image in the second phase is an ultrasound image created by separating the subharmonic wave or the higher harmonic wave of the transmission frequency separated from the reflected waves used for creating the tissue image in the second phase.