A bleeder fitting structure includes a rigid first fitting member for rotating the bleeder and an elastic second fitting member connectable with the bleeder to form a flow passage. A deformation space with a certain size is defined between the first and second fitting members, whereby when the second fitting member is connected with the connection ends of different bleeders with different sizes, the second fitting member is deformed to different extents. Therefore, the second fitting member can be tightly fitted with the connection ends of different bleeders with a larger range of size to ensure that the fluid can flow through the flow passage without leakage.