We have developed a new pressure transmitter that reduces the signal drift effect for nuclear power plants. The drift is caused by hydrogen permeation and the radiolysis of silicone oil. The proposed method uses palladium, a hydrogen absorbing material, to suppress the drift due to hydrogen accumulation. The drift suppression and measurement performance of the pressure transmitter with Pd installed inside was evaluated. The experimental results in an environment equivalent to an actual plant operated for 10 years indicate that the amount of drift in the pressure transmitter with Pd was below the detection limit (＋0.01 kPa). The maximum error in the input/output characteristics was 0.16％, the error due to vibration was within ±0.1％, and the step response was 1.1 s or less. In the experiment of this research, it was confirmed that all relevant values were within those of the target performance.