The present invention discloses a current mirror circuit generating an output current flowing through an output current path according to an input current flowing through an input current path. The current mirror circuit comprises a P type transistor in the output current path, an operational amplifier, and a basic circuit. The operational amplifier has a negative input coupled to a node receiving the input current, a positive input coupled to a drain of the P type transistor, and an output coupled to a gate of the P type transistor. The basic circuit comprises a first transistor in the input current path and a second transistor in the output current path. The first transistor has a gate and a drain coupled together. The second transistor has a gate coupled to the gate of the first transistor.