A current mode trimming apparatus for trimming a desired current is provided. The trimming apparatus includes a first transistor, a first resistor, an operational amplifier, a first controlled current source, and a second controlled current source. The first and second controlled current sources adjust the output current thereof respectively in accordance with the trimming data. The desired current passing through the first transistor is trimmed in a manner of increasing or decreasing current. Therefore, the invention can linearly increase or decrease the desired current by controlling the controlled current sources with the trimming data to achieve the goal of trimming.