Ultrasound signal processing device including: transmitter causing transmission array composed of all or some transducer elements of ultrasound probe to transmit ultrasound； reception aperture setter designating reception array having center position corresponding to center position of transmission array； transmission time calculator calculating, for each of measurement points arranged within area of reach of ultrasound, transmission time from transmission of ultrasound until arrival of ultrasound at measurement point； reception time calculator calculating reception time from reflection of ultrasound at measurement point until arrival of ultrasound at reception transducer element； delay amount calculator calculating total propagation time being sum of transmission time and reception time, and calculating delay amount for reception transducer element based on total propagation time； delay processor specifying reception signal value corresponding to delay amount, from reception signal sequence corresponding to reception transducer element； and adder generating acoustic line signal for measurement point based on specified reception signal value.
