An object is to provide an ultrasonic transmission efficiency improving composition for ultrasonic diagnosis which can suppress attenuation of ultrasonic waves in a skin stratum corneum to reach deeper portions of a living body, and has ultrasonic transmission efficiency stable even with temperature change during use； an ultrasonic diagnostic gel composition which is obtained by gelling the ultrasonic transmission efficiency improving composition into a gel state； and an imaging method using the ultrasonic transmission efficiency improving composition and the ultrasonic diagnostic gel composition.The solution includes an ultrasonic transmission efficiency improving composition including an aqueous solution containing hydrophilic fine particles including glycogen and/or hydrophilic fine particles including dextrin； an ultrasonic diagnostic gel composition which is obtained by gelling the ultrasonic transmission efficiency improving composition； and an imaging method using the ultrasonic transmission efficiency improving composition and the ultrasonic diagnostic gel composition.
