A semiconductor integrated circuit device may include a pad, a first voltage protection unit and a second voltage protection unit. The first voltage protection unit may be connected with the pad. The first voltage protection unit may be configured to maintain a turn-off state when a test voltage having a negative level may be applied from the pad. The second voltage protection unit may be connected between the first voltage protection unit and a ground terminal. The second voltage protection unit may be turned-on when an electrostatic voltage having a positive level may be applied from the pad. The second voltage protection unit may include a plurality of gate positive p-channel metal oxide semiconductor (GPPMOS) transistors serially connected with each other.