A software updating device is provided which executes a process for updating software used for operating vehicle-mounted equipment. The software updating device includes a controller that acquires the software and applies the software to the equipment in order to update the software. The controller is configured to: cause a warning device to output a warning when an abnormality relating to the equipment occurs. The controller is further configured to prohibit outputting of the warning by the warning device when the abnormality relating to the equipment is detected while the software update process is being executed.