To provide a sealing material which securely seals fine particles, in addition, while reducing the abutting load.
The sealing material is characterized by the followings. As shown in (a), when heads of piles 3, being inclined by abutting load, further incline toward the inclined direction under the conditions of being abutted to the outer peripheral surface 6a of a developing roller 6, they contact with neighboring piles 3 of being arrayed to a direction 2a, to thereby perform high density sealing of fine particles at the contacting part. The weaving direction of the material is inclined to a rotational direction 6b of the developing roller 6 at use conditions shown in (b), so as to make an larger angle than a prescribed angle θ of the pile 3 arrayed direction 2a to the rotational direction 6b. When fine particles of toner 8 move by the inclination of the pile 3 to the direction of a rotational axis line 7a to leap over the sealing material 1 which prevents fine particles from leakage, the leakage of the particles can be prevented, since the inclination of the piles 3 leads the particles to a reverse direction of an axis line 5a.