A sprayer with a changeable volume includes a container, a pump, a first pipe, a second pipe and a nozzle. The container includes an upper wall and a lower wall. The upper wall can be compressed while not containing water and extensible for containing water. The lower wall is connected to the upper wall. The pump is positioned in a space defined in the lower wall. The first pipe is directed to the pump from a space defined in the upper wall. The second pipe is directed to the exterior of the container from the pump. The nozzle is connected to the second pipe.