To provide an automatic faucet and a washing system equipped with the automatic faucet capable of performing stable operation even in the automatic faucet with a sensor unit circuit integrated in high density.

The automatic faucet is provided with a spout; a water discharge port provided at the spout; a sensor unit provided in juxtaposition with the water discharge port: a solenoid valve for controlling opening/closing of a water passage leading to the water discharge port; a control part for controlling the operation of the solenoid valve based on output signals from the sensor unit; and a connecting line for connecting the spout to the earth.