A fluid damper device may include a tube-shaped case including a bottom wall, a tube part extended from the bottom wall, and a partitioning protruded part protruded to an inner side from an inner peripheral face of the tube part, and a turning shaft including a body part facing a first end face of the partitioning protruded part, and a flange part which is enlarged from the body part and faces a second end face of the partitioning protruded part, a valve body supported by the body part, and fluid filled within the case. The first end face of the partitioning protruded part is provided with a first rib protruded toward the body part and extended in the axial line direction and a second rib protruded toward the body part and extended in the axial line direction at a position separated in a circumferential direction from the first rib.