Inspired by the work of Górnicki in his recent article [J. Górnicki, Fixed Point Theory Appl., 2017 (2017), 10 pages], where he introduced a new class of self mappings called F-expanding mappings, in this paper we introduce the concept of F m -contractive and F m -expanding mappings in M-metric spaces. Also, we prove the existence and uniqueness of fixed point for such mappings.