A biological information processing apparatus, including: a conversion element which receives an ultrasonic wave transmitted from a subject and converts the ultrasonic wave into an analog signal an analog-digital converting unit a first memory which records a digital signal a signal processing unit which outputs information on an inside of a biological body from the signal recorded in the first memory a second memory which records information on an ineffective area, for which information need not be recorded and a controlling unit which controls activation of the analog-digital converting unit or recording to the first memory, wherein the controlling unit stops the activation of the analog-digital converting unit or recording to the first memory in a period in which the ultrasonic wave transmitted from the ineffective area is received based on the information recorded in the second memory.
