A valve drive device may include a motor, a rotational member rotated by the motor, a linearly moving member engaged with the rotary member, a converting mechanism for converting rotation of the rotational member into linear movement of the linearly moving member, a diaphragm valve for opening or closing an opening part by linearly moving member, and an urging member for closing the opening part through the diaphragm valve. The linearly moving member is linearly moved by the rotational member and the opening part is closed by the diaphragm valve in a state that the rotational member and the linearly moving member are in a non-engagement state. The valve drive device may be mounted on a pump having an inflow path and a plurality of outflow paths.