A pump mechanism is provided, including a housing, a first impeller, a second impeller, and two driving modules. The housing includes a first recess, a second recess, a plate, a channel, an input pipe, a first output pipe, and a second output pipe. The plate is disposed between the first recess and the second recess. The channel passes through the plate and communicated with the first recess and the second recess. The input pipe is connected to the channel and passes through the housing and the plate. The first output pipe and the second output pipe are respectively communicated with the first recess and the second recess.