The present invention discloses an electrostatic discharge protection circuit having time-extended discharging mechanism. A RC circuit is coupled between an ESD input terminal that receives an ESD input and a ground terminal and includes an input control terminal. An inverter includes a P-type transistor coupled between the ESD input terminal and an output control terminal and an N-type transistor circuit including N-type transistors coupled in series and between the output control terminal and a ground terminal, wherein two of the N-type transistors has an internal connection terminal. Gates of the P-type transistor and N-type transistors are controlled by the input control terminal. A switch transistor is coupled between the ESD input terminal and the internal connection terminal. A discharging transistor is coupled between the ESD input terminal and the ground terminal. The gates of the switch transistor and the discharging transistor are controlled by the output control terminal.