A control device for a compression ignition engine configured to cause fuel injected into a combustion chamber from an injector to combust by compression ignition, comprising: an intake-air-temperature sensor configured to acquire an intake air temperature that is a temperature of intake air supplied to the combustion chamber; and a processor configured to control an injection amount and an injection timing of the fuel by the injector, wherein the processor is configured to cause the injector to perform a pre-injection in which fuel is injected before a compression top dead center, and a main injection in which fuel is injected during combustion of the fuel injected by the pre-injection, and wherein the processor is configured to set the fuel injection timings of the pre-injection and the main injection so that an interval between a first peak (HAp) of a heat release rate resulting from the combustion of the fuel injected by the pre-injection and a second peak (HBp) of the heat release rate resulting from the combustion of the fuel injected by the main injection becomes an interval to make pressure waves caused by the combustions of the fuel of the pre-injection and the main injection cancel each other out, characterized in that when an increase of the intake air temperature is detected by the intake-air-temperature sensor, the processor is configured to control the injector to reduce the injection amount of the pre-injection and retard the injection timing of the pre-injection compared with a case where the increase of the intake air temperature is not detected under a condition that an engine load and an engine speed are the same, and when a decrease of the intake air temperature is detected by the intake-air-temperature sensor, the processor is configured to control the injector to increase the injection amount of the pre-injection and advance the injection timing of the pre-injection compared with a case where the decrease of the intake air temperature is not detected under a condition that an engine load and an engine speed are the same. an intake-air-temperature sensor configured to acquire an intake air temperature that is a temperature of intake air supplied to the combustion chamber; and a processor configured to control an injection amount and an injection timing of the fuel by the injector, wherein the processor is configured to cause the injector to perform a pre-injection in which fuel is injected before a compression top dead center, and a main injection in which fuel is injected during combustion of the fuel injected by the pre-injection, and wherein the processor is configured to set the fuel injection timings of the pre-injection and the main injection so that an interval between a first peak (HAp) of a heat release rate resulting from the combustion of the fuel injected by the pre-injection and a second peak (HBp) of the heat release rate resulting from the combustion of the fuel injected by the main injection becomes an interval to make pressure waves caused by the combustions of the fuel of the pre-injection and the main injection cancel each other out, characterized in that when an increase of the intake air temperature is detected by the intake-air-temperature sensor, the processor is configured to control the injector to reduce the injection amount of the pre-injection and retard the injection timing of the pre-injection compared with a case where the increase of the intake air temperature is not detected under a condition that an engine load and an engine speed are the same, and when a decrease of the intake air temperature is detected by the intake-air-temperature sensor, the processor is configured to control the injector to increase the injection amount of the pre-injection and advance the injection timing of the pre-injection compared with a case where the decrease of the intake air temperature is not detected under a condition that an engine load and an engine speed are the same.