A cleaner includes a first cleaning module including a left spin mop and a right spin mop that come into contact with a floor while rotating in a clockwise direction or in a counterclockwise direction when viewed from an upper side, a second cleaning module that comes into contact with the floor at a position spaced apart from the left spin mop and the right spin mop in a forward-and-backward direction, a body supported by the first cleaning module and the second cleaning module, and a water supply module that supplies water to the first cleaning module. A water tank is disposed inside the body. Water supplied by the water supply module reaches the first cleaning module before reaching the floor.