Recent progress of experimental studies on the gas-phase reaction dynamics of transition metal (TM) atoms carried out in our laboratory are presented. Reactions of transition metal atoms have provided an important class of systems for the study of reaction dynamics. Because TM atoms usually have several low lying electronic states, the interactions of the potential energy surfaces evolved from these states play important roles in their reactions. In order to clarify these interactions, preparation of the TM atoms in a selected electronic state and detection of products in a specific electronic state are necessary from the experimental viewpoint. The single collision condition is also essential. Crossed-beam laser-induced fluorescence technique has been applied for several oxidation reactions of metal atoms. The laser-vaporization TM beam source combined with several carrier gases is used to generate a single electronic state or their combination with known populations. They enable us to extract noble information about the reactivities of the specific electronic states. The analysis of Doppler profiles of product, O(3PJ), is also useful to determine branching ratios of products in different electronic states.