Structure for mounting switch on vehicular steering wheel

An outer casing (4) of a switch (3) is provided with mounting hooks (9), which are engaged with a core metal (11) of a steering wheel (1). A lower cover (12) of the steering wheel (1) is provided with retaining portions (13), which are made to abut against the mounting hooks (9) in such a way as to restrain the retaining portions (13) from moving in a direction in which the engagement between the core metal (11) and each of the retaining portions (13) is canceled. Consequently, the switch 3 (is) firmly mounted on the steering wheel (1). Thus, a stable mounting state of the switch (3) is obtained.