Freezing diagnosing device and engine control apparatus

A freezing diagnosing device to be installed in an engine includes an ambient temperature sensor, a liquid temperature sensor, and a freezing determination unit. The ambient temperature sensor detects an ambient temperature. The liquid temperature sensor detects the temperature of a liquid held in the engine. The freezing determination unit determines that a freezing state of a pipe coupled to a pressure sensor in the engine is established when one or both of a first condition and a second condition are satisfied. The first condition is that the ambient temperature detected by the ambient temperature sensor is equal to or less than a first threshold. The second condition is that the temperature of the liquid detected by the liquid temperature sensor is equal to or less than a second threshold.