A rotary atomizer head for an electrostatic paint applicator, having a paint space for receiving paint supplied from a paint feed tube and a spoon-cut groove formed in the bottom surface of the paint space, comprising: a bell-shaped atomizer head body, and a functional member made of a synthetic resin, which is accessible from a front face of the atomizer head body into a central recess of the atomizer head body, the functional member being removably disposed in the central recess of the atomizer head body, wherein the functional member includes: a sidewall extending continuous in a circumferential direction; wherein the circumferentially continuous sidewall of the functional member has an outer circumferential surface having a complementary configuration with the peripheral wall of the central recess, and the outer circumferential surface of the sidewall of the functional member is substantially in contact with the peripheral wall of the central recess; wherein the circumferentially continuous sidewall of the functional member has an inner circumferential surface contiguous to the spoon-cut groove; wherein the functional member has a plurality of paint outlets formed at circumferential intervals to communicate with the paint space; and wherein the paint outlets are contiguous to the inner circumferential surface of the sidewall of the functional member; characterized in that the functional member includes: a plurality of legs extending rearward from a rear end of the sidewall in circumferential alignment at intervals from each other; and a claw provided at a free end of each leg to engage with a circumferential groove formed in a peripheral wall of the central recess of the atomizer head body, wherein the peripheral wall of the central recess of the atomizer head body; gradually increases forward in diameter by an angle of inclination. a bell-shaped atomizer head body, and a functional member made of a synthetic resin, which is accessible from a front face of the atomizer head body into a central recess of the atomizer head body, the functional member being removably disposed in the central recess of the atomizer head body, wherein the functional member includes: a sidewall extending continuous in a circumferential direction; wherein the circumferentially continuous sidewall of the functional member has an outer circumferential surface having a complementary configuration with the peripheral wall of the central recess, and the outer circumferential surface of the sidewall of the functional member is substantially in contact with the peripheral wall of the central recess; wherein the circumferentially continuous sidewall of the functional member has an inner circumferential surface contiguous to the spoon-cut groove; wherein the functional member has a plurality of paint outlets formed at circumferential intervals to communicate with the paint space; and wherein the paint outlets are contiguous to the inner circumferential surface of the sidewall of the functional member; characterized in that the functional member includes: a plurality of legs extending rearward from a rear end of the sidewall in circumferential alignment at intervals from each other; and a claw provided at a free end of each leg to engage with a circumferential groove formed in a peripheral wall of the central recess of the atomizer head body, wherein the peripheral wall of the central recess of the atomizer head body; gradually increases forward in diameter by an angle of inclination.