To take out an instrument desired to be taken out after turning it to a position without a danger without using hands of an operator when the operator takes out an instrument that he/she wants to use from an instrument holder.

The plurality of instruments 8 (81-84) are disposed in parallel on the instrument holder 5. When performing dental treatment, the operator pulls out the instrument that he/she wants to use and performs the dental treatment while controlling a rotation speed or the like by a foot controller 6. When the lever 6a of the foot controller 6 is moved to the left and right (direction B) by a foot operation when all the instruments 81-84 are mounted on the instrument holder 5, the instrument holder 5 is moved to the left and right (direction A) in linkage with the movement and is brought to a position at which the instrument desired to be taken out can be pulled out straight.