A toner includes a plurality of toner particles that each include a core and a shell layer disposed over a surface of the core. The shell layer contains a unit derived from a thermoplastic resin and a unit derived from a monomer or prepolymer of a thermosetting resin. A surface of each of the toner particles has a Young's modulus that changes by a proportion of no greater than 20% from 30° C. to 50° C., and changes by a proportion from 50° C. to 70° C. that when divided by the proportion of change from 30° C. to 50° C., yields a value of at least 3.0 and no greater than 10.0. The Young's modulus is measured in a state in which an external additive is not adhered to the toner particle using a scanning probe microscope while raising a cantilever temperature thereof.