Technique that enables precisely measuring cavity height and precisely grasping maximum transmission sound pressure in an ultrasonic probe is provided to the ultrasonic probe using CMUT. The ultrasonic probe according to the present invention includes plural cells each of which includes a lower electrode and an upper electrode arranged via a gap with respect to the lower electrode, and the plural cells include an ultrasonic cell the gap of which is void and which transmits/receives an ultrasonic wave and a reference cell the gap of which is filled with a conductive material. Electrostatic capacity of the ultrasonic cell and the reference cell is measured, parasitic capacity included in the measured electrostatic capacity as to the ultrasonic cell is corrected using parasitic capacity included in the measured electrostatic capacity as to the reference cell, and cavity height is calculated on the basis of the corrected electrostatic capacity of the ultrasonic cell.