The present invention relates to a water turbine in which a unit pipe can be joined by an optional number and a rotating shaft integrated with a rotor can be joined by an optional number according to intended use or condition of use, and by which each rotor can be supported stably. A water turbine in which a rotor provided in a water conduit pipe is rotated by a water flow in the water conduit pipe and the rotation of the rotor is utilized as a motive power, wherein pluralities of the unit pipes constituting a part of the water conduit pipe are connected in order by interposing an end plate having a bearing and a water passing part between respective them, wherein pluralities of rotating shafts respectively integrated with the rotor are linearly connected by providing a connecting means between respective them while end portions opposing to each other of a pair of adjacent rotating shafts are brought into contact, wherein each of the rotating shafts is rotatably supported by respective pair of bearings arranged to neighbor each other such that at least one of the rotors is arranged between the respective pair of bearings, and thereby forming a water turbine unit.