This paper proposes a method for predicting human posture by thermal array sensors. In our previous work, we studied a system for estimating human posture by the sensors. The system successfully estimated human posture for elderly people living in a nursing home. As a further step to our previous work, this paper presents a human posture prediction method using Bayesian inference with the sensors. Our method predicts that posture changes at the next sample with Bayesian inference which employs characteristics of a past posture. In the experiment, we applied the results of our previous work and synthesized data of assumed daily movements. In conclusion, we obtained the basis of an effective posture prediction method using Bayesian inference and a thermal array sensor network.