A fuel tank connector includes an upper chamber provided with a first communication portion relative to a ventilation flow path; and a lower chamber provided with a third communication portion relative to the upper chamber. A bowl-shaped portion narrowing downward is formed in a bottom portion of the upper chamber, and the third communication portion is formed in a bottom of the bowl-shaped portion. A cover body having a container shape, including a top portion and a side portion and opening at a lower face is supported directly above the third communication portion with a ventilation interval between the open edge and the third communication portion.