A fuel cell exhaust device includes a pipe having one side open and the other side closed, a water tank having one side open and the other side closed, a reformer exhaust pipe communicating with the pipe between one side and the other side of the pipe, a stack exhaust pipe which is spaced apart from the reformer exhaust pipe and communicates with the pipe between one side and the other side of the pipe, a drain pipe positioned adjacent to the reformer exhaust pipe or the stack exhaust pipe and disposed on an outer circumferential surface of the water tank to communicate with the inside of the water tank, and a hole defined on the closed other side of the pipe and spaced apart from the closed other side of the water tank.