PROBLEM TO BE SOLVED: To provide an ultrasonic probe which can reduce the difference of displacement magnitude of a membrane between an ON cell adjacent to an OFF cell and an ON cell not adjacent to the OFF cell in a capacitive micromachined ultrasonic transducer (CMUT).SOLUTION: An ultrasonic probe includes a plurality of cells which respectively have lower electrodes 301, hollow parts formed on the lower electrodes, and upper electrodes 304 formed on the hollow parts, and are arranged in a two-dimensional array. When a cell in which voltage obtained by overlapping DC voltage and AC voltage is applied between the upper electrode 304 and the lower electrode 301 and both DC voltage and AC voltage are equal to or more than desired values is determined as an ON cell, and the other cells are determined as an OFF cell among a plurality of cells, the DC voltage is applied between the upper electrode 304 and the lower electrode 301 of a cell 308 adjacent to an ON cell 307 among the OFF cells.
