The article deals with the problems of optimizing the design and structure of the moisture meter, which generally reduces to minimizing measurement errors by selecting the type of sample former and its basic parameters. The constructive, structural and algorithmic optimization methods proposed in the article allow to create a single unified complex of means for controlling the moisture content of fibrous and solid bulk materials that were used in the development of a multi-purpose microwave moisture meter for fibrous materials and granular products of the agro-industrial complex