A manual carwash nozzle structure includes a grip body, a barrel member, and a spray nozzle. The barrel member is formed of a connection body, an adjustment valve, and a detergent container. The connection body is provided with a water inlet in communication with a hose connector of the grip body, and a water outlet in communication with the water inlet and the spray nozzle. A bypass is jointly provided by the connection body and the adjustment valve, so as to allow a portion of incoming water in the water inlet to enter the detergent container in which a water-detergent mixture is formed. The mixture is let out of the container into the water outlet via the bypass.