A nozzle holder that detachably holds a nozzle in a lower end portion of a main shaft is configured to have a tubular shape having an insertion hole into which an installed portion of the nozzle is inserted, and to include a holder tube portion in which an opening portion leading to the insertion hole is formed on one side surface of the holder tube portion, a clamp lever which has an engaging portion engaged via the opening portion with the installed portion of the nozzle inserted into the insertion hole, and a clamp spring which biases the engaging portion to the installed portion of the nozzle inserted into the insertion hole.