An object information acquiring apparatus, comprising: a probe including a plurality of conversion elements configured to transmit acoustic waves to an object, receive reflected waves that were reflected within the object, and convert the reflected waves into time-series received signals; and a processor (006, 007, 010) configured to perform frequency domain interferometry, through application of adaptive signal processing, by using a plurality of the received signals output from the plurality of conversion elements and a reference signal, and obtain acoustic properties of a plurality of positions in the object; wherein the object information acquiring apparatus is characterized in that: the probe is configured such that, when a direction in which the plurality of conversion elements are arranged is a first direction and a direction which intersects with the first direction is a second direction, end portions of each of the conversion elements in the second direction have a lower transmission sound pressure of the acoustic waves than a midportion of the respective conversion element in the second direction; each of the conversion elements of the plurality of conversion elements includes a respective plurality of cells arranged in the second direction; the processor is configured such that the reference signal is determined based on a waveform of the acoustic waves that are transmitted from the conversion elements to a predetermined depth of the object; and the processor is configured to switch the reference signal according to the depth at which the plurality of conversion elements transmit the acoustic waves to the object. a probe including a plurality of conversion elements configured to transmit acoustic waves to an object, receive reflected waves that were reflected within the object, and convert the reflected waves into time-series received signals; and a processor (006, 007, 010) configured to perform frequency domain interferometry, through application of adaptive signal processing, by using a plurality of the received signals output from the plurality of conversion elements and a reference signal, and obtain acoustic properties of a plurality of positions in the object; wherein the object information acquiring apparatus is characterized in that: the probe is configured such that, when a direction in which the plurality of conversion elements are arranged is a first direction and a direction which intersects with the first direction is a second direction, end portions of each of the conversion elements in the second direction have a lower transmission sound pressure of the acoustic waves than a midportion of the respective conversion element in the second direction; each of the conversion elements of the plurality of conversion elements includes a respective plurality of cells arranged in the second direction; the processor is configured such that the reference signal is determined based on a waveform of the acoustic waves that are transmitted from the conversion elements to a predetermined depth of the object; and the processor is configured to switch the reference signal according to the depth at which the plurality of conversion elements transmit the acoustic waves to the object. the probe is configured such that, when a direction in which the plurality of conversion elements are arranged is a first direction and a direction which intersects with the first direction is a second direction, end portions of each of the conversion elements in the second direction have a lower transmission sound pressure of the acoustic waves than a midportion of the respective conversion element in the second direction; each of the conversion elements of the plurality of conversion elements includes a respective plurality of cells arranged in the second direction; the processor is configured such that the reference signal is determined based on a waveform of the acoustic waves that are transmitted from the conversion elements to a predetermined depth of the object; and the processor is configured to switch the reference signal according to the