To provide a faucet provided with amenity while urging a user himself or herself to save water.

This faucet mounting unit with illumination provided with an adaptor part for mounting the unit to a faucet, and a housing provided with a duct for the passage of water, is provided with a means for sensing a water current flowing in the duct, a current supply means and a light emitting means inside the housing. When sensing the water current, a current is supplied to the light emitting means from the supply means to emit light to thereby illuminate the water which flows out.