Disclosed is an apparatus that transmits an elastic wave to an object and receives a reflected wave, this apparatus including: a transmitting and receiving unit having elements for converting an elastic wave to an electric signal, and being arranged at least in one direction an element controlling unit that inputs an electric signal to the element and causes the element to transmit an elastic wave and a detecting unit that detects a reflected wave to be received by the element, wherein the electric signal to be inputted to the element is an encoded pulse signal encoded among the elements, and the detecting unit decodes the reflected wave and executes at different time points aperture synthesis processing of synthesizing the decoded reflected wave with respect to the intersections of two axes at different time points.
