A paint roller comprises a liquid-impermeable tubular core member 6 with an engaging element 9 having a male structure of a separable fastener and a height of 0.3 to 4.0 mm on a surface thereof, and a cover member 8 with a female structure and a loop on the inner surface capable of male-female engaging with the engaging element on the surface of the core member. The density of the engaging element on the surface of the core member is 30 to 150/cm2. Thus, in such paint roller, when the cover member becomes dirty, damaged, or worn, the cover member can be exchanged to a new cover member. Such that, a roller body is repeatedly usable, and the paint roller can provide a good painted surface. Moreover, there is also provided an effect roller in which a painting pattern can be changed optionally.