A control device of a compression-ignition engine is provided. The control device includes the engine having a cylinder, an exhaust gas recirculation system for introducing exhaust gas into the cylinder, and a controller for operating the engine by compression-ignition combustion of mixture gas inside the cylinder within a predetermined compression-ignitable range on a low engine load side. Within the compression-ignitable range, the controller sets an EGR ratio higher as the engine load becomes lower, and the controller sets the EGR ratio to a predetermined highest EGR ratio when the engine load is at a specific load that is on the low engine load side within the compression-ignitable range. When the engine load is lower than the specific load, the controller sets the EGR ratio to be lower than the highest EGR ratio.