To provide a vibration-proof structure for a piano leg which prevents string vibration of the piano from being conducted to a floor through the piano leg without spoiling the function of a caster.

The front piano leg 10 of a grand piano GP has a caster 18 at its lower end, and is fitted to a shelf 12 as one constituent member of a piano main body 1 through a vibration-proof member 2 made of hard rubber. The rear piano leg 10 has a caster 18 at its lower end as well and is fitted to a leg bearing seat 16 as one constituent member of the piano main body 1 across a vibration-proof member 2. The leg bearing seat 16 is fitted to a column 13 across a leg support 14. This grand piano GP prevents string vibration from being conducted to the piano leg 10 through the shelf 12 and leg bearing seat 16 from the piano main body by the vibration-proof member 2 when strings are hit. Consequently, this structure gives the effect that residents living below the floor do not feel unpleasant owing to its noise.