A filter device includes a cylindrical filter, a lid member, and an urging member. The filter catches foreign matter contained in gaseous fuel. The filter has a first opening located in one end and a second opening located in the other end of the filter opposite to the first opening. The filter is arranged in the drain tank with the first opening closed with a wall member such that gaseous fuel is allowed to be drawn into the filter through the inflow portion. The gaseous fuel that has passed through the filter flows out of the drain tank through the outflow portion. The lid member closes the second opening of the filter. The urging member urges the lid member toward the filter.