There is provided an ultrasonic imaging apparatus capable of optimizing parameters in frequency compound imaging. The ultrasonic imaging apparatus includes an optimal parameter calculation unit that calculates optimal values of processing parameters in the frequency compound imaging, and the optimal parameter calculation unit outputs a result that satisfies c.sub.1 .sigma..sub.1=c.sub.2 .sigma..sub.2= . . . c.sub.n .sigma..sub.n where the number of divided frequency bands is n, a bandwidth of a divided signal is .sigma..sub.i and a signal intensity at the time of addition is c.sub.i (i=1, 2, . . . , n).