To provide a mass mounting structure for an eye part of a leaf spring capable of fixing a mass on the eye part of the leaf spring, which was impossible conventionally, and capable of restraining amplitude of the eye part.

This mass mounting structure is for mounting the damping mass 3 on the eye part 1a formed on an end part of the leaf spring 1 in an almost arc shape on the side view. The mass 3 is welded on an outer peripheral surface 8c side of an end part 8a, and a stay 8 formed almost in an arc shape along an outer peripheral shape of the eye part 1a is fitted onto the outer periphery of the eye part 1a. A screw hole 3a and a hole 8e are respectively penetrated toward the center of the eye part 1a between a lower surface of the mass 3 and an inner peripheral surface 8d of the stay 8. A bolt 9 is screwed into the screw hole 3a, the outer peripheral surface of the eye part 1a is pressed with a tip of the bolt 9, and thereby the stay 8 is fixed on the eye part.