To provide an engine system with which in a case where a power supply voltage whose specification is to be changed is higher than an expected voltage, the specification of the power supply voltage from an alternating-current power supply can be changed at low cost without providing an additional transformer.An engine system 100 includes a transformer 130, a power receiving device 140, and a switcher 150, and switcher 150 connects a switching terminal 151 connected to one power receiving terminal 141 of the power receiving device 140 to either a first terminal 152 connected to one terminal 134 of a primary 131 or a second terminal 153 connected to a branch terminal 136. The engine system 100 is configured such that the other power receiving terminal 142 of the power receiving device 140 and the other terminal 135 of the primary 131 are connected and the primary 131 and an alternating-current power supply 200 are electrically connected.