A water spray gun for control of an outflow of water and adjustment of the amount of the outflow is revealed. The water spray gun includes a handle portion, a pipe portion connected to the handle portion and used for spraying water, and a control device arranged at the position where the pipe portion meets the handle portion. The control device comprises a press part and a rotary control member. The amount of the water outflow is controlled by the rotary control member. The amount of the outflow sprayed out from the pipe portion at respective stages is continuously controlled and regulated by the control device.