An ultrasonic body tissue detecting device , comprising: a transmission/reception unit configured to transmit an ultrasonic signal into a body of a sample and to receive an echo signal of the ultrasonic signal; and a two-dimensional data acquisition unit configured to acquire two-dimensional data in a transmitting direction of the ultrasonic signal and in a scanning direction substantially perpendicular to the transmitting direction of the ultrasonic signal, based on the echo signals acquired at a plurality of positions along the surface of the sample, and to form two-dimensional echo image data using the two-dimensional data; characterized by : a spatial frequency distribution calculation unit configured to perform a spatial frequency conversion of the two-dimensional echo image data, two-dimensionally into a depth direction of the body and into a horizontal direction perpendicular to the depth direction, and to calculate a spatial frequency distribution for a determining position; and a determination unit configured to determine whether the determining position is muscular tissue or subcutaneous tissue based on a distribution of a frequency component in the depth direction and a distribution of a frequency component in the horizontal direction of the spatial frequency distribution. a transmission/reception unit configured to transmit an ultrasonic signal into a body of a sample and to receive an echo signal of the ultrasonic signal; and a two-dimensional data acquisition unit configured to acquire two-dimensional data in a transmitting direction of the ultrasonic signal and in a scanning direction substantially perpendicular to the transmitting direction of the ultrasonic signal, based on the echo signals acquired at a plurality of positions along the surface of the sample, and to form two-dimensional echo image data using the two-dimensional data; characterized by : a spatial frequency distribution calculation unit configured to perform a spatial frequency conversion of the two-dimensional echo image data, two-dimensionally into a depth direction of the body and into a horizontal direction perpendicular to the depth direction, and to calculate a spatial frequency distribution for a determining position; and a determination unit configured to determine whether the determining position is muscular tissue or subcutaneous tissue based on a distribution of a frequency component in the depth direction and a distribution of a frequency component in the horizontal direction of the spatial frequency distribution. a spatial frequency distribution calculation unit configured to perform a spatial frequency conversion of the two-dimensional echo image data, two-dimensionally into a depth direction of the body and into a horizontal direction perpendicular to the depth direction, and to calculate a spatial frequency distribution for a determining position; and a determination unit configured to determine whether the determining position is muscular tissue or subcutaneous tissue based on a distribution of a frequency component in the depth direction and a distribution of a frequency component in the horizontal direction of the spatial frequency distribution. <EOS>