A fixing structure of a resin tank for stably keeping the resin tank being fixed includes: a first holder having a predetermined length and being disposed corresponding to a pressed portion of a resin tank; a biasing member that is disposed in the first holder; a pressing member that is supported by the first holder and projects toward the pressed portion by a biasing force of the biasing member; and a pair of rods respectively having first ends attached to both ends of the first holder in a longitudinal direction and second ends attached to a frame.