A liquid fuel level sensing device disclosed herein may include: a holder; an arm fixed to the holder; a cover fixed to the holder to cover the arm; and a float connected to the arm outside the holder. The holder may include a bottom portion and a first snap fit structure, which may include a pair of support portions provided with an interval therebetween, and provided on the bottom portion. First and second interval portions may be provided between the pair of support portions, the first interval portion may hold the arm, and the second interval portion may be provided above the first interval portion and be narrower than a width of the arm held in the first interval portion. The cover may include a deformation restricting portion provided at a position facing an outer surface of at least one of the pair of support portions.