Antitheft apparatus for equipment with prime mover

In an apparatus for preventing theft of equipment (electric motor) having a prime mover (motor), a prime mover controller, a starter switch (20g) that allows the operator to connect/disconnect power from a power source to the prime mover; and an authenticator that acquires ID information from an electronic key through a receiver (34c) when the key is brought close thereto by the operator, and permits the controller to start the prime mover when acquired ID information is determined to correspond with authentication ID information, the starter switch (20g) is made of electrode pair (50) that is sensitive to electrostatic capacitance, and the starter switch (20g) and the receiver are installed together on an electronic circuit board (42), thereby achieving the smaller structure of the apparatus.