PROBLEM TO BE SOLVED: To provide an ultrasound diagnostic device capable of suppressing a decrease in image quality of ultrasound images more easily while suppressing a decrease in efficiency of a power supply part.SOLUTION: An ultrasound diagnostic device (1) that displays an ultrasound image on the basis of a received signal by an ultrasound probe with respect to an ultrasound wave reflected within a subject comprises: a power supply part (11) that includes at least one voltage conversion circuit (111) for converting input voltage into power supply voltage and then outputting it. The voltage conversion circuit has a coil (L), has a switching element (Tr) for switching a course of electric current flowing through the coil in accordance with a prescribed switching control signal, and outputs power supply voltage by repeating a switching operation in a state where the input voltage is supplied. The power supply part is provided with multiple coils, and the coils are arranged at such positions that a leakage magnetic field near an opening of at least one coil of the coils is partially cancelled by a leakage magnetic field from one or more other coils.SELECTED DRAWING: Figure 4【課題】電源部の効率低下を抑えつつ、より容易に超音波画像の画質の低下を抑制することができる超音波診断装置を提供する。【解決手段】被検体内で反射された超音波の超音波探触子による受信信号に基づいて超音波画像を表示させる超音波診断装置（１）は、入力電圧を所定の電源電圧に変換して出力する電圧変換回路（１１１）が少なくとも一つ設けられた電源部（１１）を備え、電圧変換回路は、コイル（Ｌ）と、所定の切替制御信号に応じてコイルに流れる電流の経路を切り替えるスイッチング素子（Ｔｒ）とを有し、入力電圧が供給された状態で切替動作が繰り返し行われることで電源電圧を出力し、電源部には、複数のコイルが設けられ、複数のコイルは、当該複数のコイルのうち少なくとも一のコイルの開口部近傍における漏洩磁界の一部が、他の一以上のコイルからの漏洩磁界により打ち消される位置関係で配置されている。【選択図】図４
