An electric toothbrush head includes a brush body. The brush body includes an insertion cavity and a plug-in unit inserted into the insertion cavity. The plug-in unit includes a friction arm and an elastic arm cooperatively forming a pressing channel therebetween. The elastic arm has a bending section with a pressing surface facing the pressing channel. The friction arm has a convex section with a friction surface facing the pressing channel. The pressing surface and a concave-convex structure of the convex section press opposite sides of a vibration unit to fix the vibration unit in the pressing channel. The convex section has a concave surface facing an inner side wall of the insertion cavity, with a curved interval formed between the concave surface and the inner side wall. An elastic rubber block is filled in the curved interval and the elastic rubber block abuts against the inner side wall.