An occupant protection device controller includes a main sensor, a safing sensor, a main control circuit, a sub control circuit, and a trigger signal output circuit. Whereas the main control circuit has a CPU, and the sub control circuit has no CPU. The main control circuit determines whether to output a main control signal based on both an output of the main sensor and an output of the safing sensor. The sub control circuit has a comparator and determines whether to output a sub control signal based on a comparison of the output of the main sensor with a threshold value. The trigger signal output circuit outputs a trigger signal for activating an occupant protection device upon receipt of both the main control signal and the sub control signal.