A secondary battery includes a positive electrode, a negative electrode, and an electrolyte. The negative electrode includes a negative electrode active material capable of electrochemically absorbing and releasing lithium ions, and the negative electrode active material includes a first composite material containing a silicate phase and silicon particles dispersed in the silicate phase. The silicate phase includes at least one of an alkali metal and an alkaline earth metal. The content of the silicon particles in the first composite material is 30 mass % or more and 80 mass % or less. The electrolyte includes lithium fluorosulfonate.