A transfer device can have a high durability and no limit in an operation of an arm member. An electrostatic pick 44 of a first transfer device 17 is advanced into a process module 12, and a wafer W is electrostatically attracted to and held on the electrostatic pick 44. While the wafer W is being transferred into a load lock module 14 by driving the first transfer device 17, the electrostatic pick 44 is turned into an electrically floating state, so that a state in which the wafer W is electrostatically attracted to and held on the electrostatic pick 44 is maintained. After the transferring of the wafer W to the load lock module 14 is completed, charges of the electrostatic pick 44 are neutralized, so that the wafer W is not electrostatically attracted to and held on the electrostatic pick 44.