An ultrasonic image generating device (100) which generates a cross-sectional image (205) of a specific cross-section of a subject from a plurality of ultrasonic images (201) obtained by scanning the subject from a plurality of directions using an ultrasonic probe (101), includes a cross-section position identifying unit (111) which obtains cross-section information (202) indicating a position and an orientation of the specific cross-section a positional information obtaining unit (110) which obtains positional information (203) including a position and an orientation of each of the ultrasonic images (201) of the subject a reference image selecting unit (196) which selects at least one of the ultrasonic images as a reference image, the at least one of the ultrasonic images having a distance from the specific cross-section that is less than a first threshold and an orientation difference from the specific cross-section that is less than a second threshold and a cross-sectional image generating unit (197) which generates the cross-sectional image (205) using the reference image.
