A fluid transmission apparatus comprising: a stator having a room defined therein and the room having a circular inner periphery, the stator having an inlet and an outlet, the inlet and the outlet communicating with the room; a rotor having a cylindrical body and a shaft which extends through the cylindrical body, the cylindrical body eccentrically located in the room, an outer periphery of the cylindrical body being tangent to the inner periphery of the room, the inlet and the outlet respectively located adjacent to a position where the outer periphery of the cylindrical body is tangent to the inner periphery of the room, two slots defined diametrically in the outer periphery of the cylindrical body and communicating with the room, the shaft extending through the stator and adapted to be connected with a power source; two blades (32, 34) respectively located within the slots, a first end of each blade (32, 34) pointing an axis of the cylindrical body, a second end of each blade (32, 34) being in contact with the inner periphery of the room so as to form a space for receiving fluid between the outer periphery of the cylindrical body and the inner periphery of the room; two first pieces and two second pieces respectively pivotably connected to the stator, the first pieces being located adjacent to an underside of the cylindrical body and the second pieces being located adjacent to a top of the cylindrical body, the first pieces and the second pieces pivoted about a center of the room and the two blades (32, 34) respectively and pivotably connected to the first pieces and the second pieces by two respective axles (322, 342), the blades (32, 34) being pivotable about the center of the room and linearly movable within the slots, a curved face (324/344) defined in the second end of each of the two blades (32, 34) and being in contact with the inner periphery of the room, the inner periphery of the room having a radius R1, each of the axles (322, 342) being pivotable by a radius R2, the curved face (324/344) of the second end of each of the two blades (32, 34) having a radius R3, R3=R1-R2, the two blades (32, 34) and the first pieces being pivoted about two respective centers of the curved faces (324, 344) such that the second ends of the two blades (32, 34) are in contact with the inner periphery of the room. a stator having a room defined therein and the room having a circular inner periphery, the stator having an inlet and an outlet, the inlet and the outlet communicating with the room; a rotor having a cylindrical body and a shaft which extends through the cylindrical body, the cylindrical body eccentrically located in the room, an outer periphery of the cylindrical body being tangent to the inner periphery of the room, the inlet and the outlet respectively located adjacent to a position where the outer periphery of the cylindrical body is tangent to the inner periphery of the room, two slots defined diametrically in the outer periphery of the cylindrical body and communicating with the room, the shaft extending through the stator and adapted to be connected with a power source; two blades (32, 34) respectively located within the slots, a first end of each blade (32, 34) pointing an axis of the cylindrical body, a second end of each blade (32, 34) being in contact with the inner periphery of the room so as to form a space for receiving fluid between the outer periphery of the cylindrical body and the inner periphery of the room; two first pieces and two second pieces respectively pivotably connected to the stator, the first pieces being located adjacent to an underside of the cylindrical body and the second pieces being located adjacent to a top of the cylindrical body, the first pieces and the second pieces pivoted about a center of the room and the two blades (32, 34) respectively and pivotably connected to the first pieces and the second pieces by two respective axles (322, 342), the blades (32, 34) being pivotable about the center of the room and linearly movable within the slots, a curved face (324/344) defined in the second end of each of the two blades (32, 34) and being in contact with the inner periphery of the room, the inner periphery of the room having a radius R1, each of the axles (322, 342) being pivotable by a radius R2, the curved face (324/344) of the second end of each of the two blades (32, 34) having a radius R3, R3=R1-R2, the two blades (32, 34) and the first pieces being pivoted about two respective centers of the curved faces (324, 344) such that the second ends of the two blades (32, 34) are in contact with the inner periphery of the room.