A work unit power supply device configured to supply power to multiple work units (81, 82, 83) constituting a work device as power supply targets, the work unit power supply device comprising: a first power supply line through which power supply is stopped when an emergency stop condition is satisfied; a second power supply line through which power supply is not stopped even when the emergency stop condition is satisfied, wherein the first power supply line and the second power supply line are capable of being used individually according to a difference in a safety level of each work unit (81, 82, 83), wherein a first type work unit, which has low safety and is supplied with power from only the first power supply line, a second type work unit, which has high safety and is supplied with power only from the second power supply line, and a third type work unit, which includes a portion having low safety and a portion having high safety and is supplied with power from both the first power supply line and the second power supply line, are set as power supply targets; a first power supply circuit configured to supply power to the first power supply line and configured to stop power supply when the emergency stop condition is satisfied; and a second power supply circuit configured to supply power to the second power supply line, wherein the work device is configured so that the multiple works units are able to be replaced, and wherein the power supply device for a work unit further comprises a power saving control section which implements at least one mode of a first power saving mode in which the first power supply circuit is stopped when the work device is configured only of the second type work unit and a second power saving mode in which the second power supply circuit is stopped when the component supply device is configured only of the first type work unit. a first power supply line through which power supply is stopped when an emergency stop condition is satisfied; a second power supply line through which power supply is not stopped even when the emergency stop condition is satisfied, wherein the first power supply line and the second power supply line are capable of being used individually according to a difference in a safety level of each work unit (81, 82, 83), wherein a first type work unit, which has low safety and is supplied with power from only the first power supply line, a second type work unit, which has high safety and is supplied with power only from the second power supply line, and a third type work unit, which includes a portion having low safety and a portion having high safety and is supplied with power from both the first power supply line and the second power supply line, are set as power supply targets; a first power supply circuit configured to supply power to the first power supply line and configured to stop power supply when the emergency stop condition is satisfied; and a second power supply circuit configured to supply power to the second power supply line, wherein the work device is configured so that the multiple works units are able to be replaced, and wherein the power supply device for a work unit further comprises a power saving control section which implements at least one mode of a first power saving mode in which the first power supply circuit is stopped when the work device is configured only of the second type work unit and a second power saving mode in which the second power supply circuit is stopped when the component supply device is configured only of the first type work unit.