To provide a dental instrument holder capable of easily adding an instrument.

This instrument holder is provided with a plurality of cassette parts 10 and a cassette holding part 20 for holding them. At the cassette part 10, a hole 11 for holding the instrument is opened on a front surface, a hole for inserting the instrument is opened on a bottom surface, and a plurality of (electrode) pins 12 are fixed on a rear surface. The cassette holding part 20 is provided with holes 21 for inserting the (electrode) pins corresponding to the plurality of cassette parts 10. Since the instrument can be held by setting the instrument to the cassette part 10 and inserting it to the cassette holding part 20, the instrument is additionally installed just by preparing the cassette part 10.