An acoustic lens for an ultrasound transducer, the acoustic lens configured to be disposed, in use, in a front end portion of an ultrasound transducer, wherein the acoustic lens has a concave front surface, the concave front surface being a surface of the acoustic lens that, in use, comes into contact with a subject being examined using the ultrasound transducer; the acoustic lens is formed from a base material in which a plurality of fine particles are dispersed, and characterised in that: as a degree of dispersion of the fine particles, wherein the degree of dispersion of the fine particles is an index representing variation of a distance between adjacent fine particles in the base material, increases from a central portion where the fine particles are locally close to each other and the arrangement positions of the fine particles in the base material are ununiformly distributed, toward both end portions in an elevation direction, where the arrangement positions of the fine particles in the base material are uniformly distributed, acoustic velocity decreases from the central portion toward both end portions in the elevation direction; and wherein the number of fine particles per unit volume is the same from the central portion to both end portions in the elevation direction. wherein the acoustic lens has a concave front surface, the concave front surface being a surface of the acoustic lens that, in use, comes into contact with a subject being examined using the ultrasound transducer; the acoustic lens is formed from a base material in which a plurality of fine particles are dispersed, and characterised in that: as a degree of dispersion of the fine particles, wherein the degree of dispersion of the fine particles is an index representing variation of a distance between adjacent fine particles in the base material, increases from a central portion where the fine particles are locally close to each other and the arrangement positions of the fine particles in the base material are ununiformly distributed, toward both end portions in an elevation direction, where the arrangement positions of the fine particles in the base material are uniformly distributed, acoustic velocity decreases from the central portion toward both end portions in the elevation direction; and wherein the number of fine particles per unit volume is the same from the central portion to both end portions in the elevation direction. as a degree of dispersion of the fine particles, wherein the degree of dispersion of the fine particles is an index representing variation of a distance between adjacent fine particles in the base material, increases from a central portion where the fine particles are locally close to each other and the arrangement positions of the fine particles in the base material are ununiformly distributed, toward both end portions in an elevation direction, where the arrangement positions of the fine particles in the base material are uniformly distributed, acoustic velocity decreases from the central portion toward both end portions in the elevation direction; and wherein the number of fine particles per unit volume is the same from the central portion to both end portions in the elevation direction.