To provide an ignition switch coupling structure capable of reducing backlash of an ignition switch and an engine operation input device in a rotation direction.

An ignition switch coupling structure has: an engine operation input device 5 having an ignition fitting recess 2 on the peripheral wall of which a coupling opening 1 is opened at a rear end; and an ignition switch 6 fitted with the ignition fitting recess 2. The ignition switch 6 is provided with an elastic tongue piece 8 resiliently fitted with the coupling opening 1 during being fitted with the ignition fitting recess 2 with a rear end as a free end, and giving a forward energization force to the ignition switch 6 by pressure-welding a tapered face formed at a free edge under a fitting state and inclined in a thickness direction with a rear edge of the coupling opening 1. A skew side inclined to, and mutually overlaying in linear contact in an insertion direction of the ignition fitting recess 2, and giving a diagonally forward energization force to the ignition switch 6 is formed at the free edge of the elastic tongue piece 8 and the rear edge of the coupling opening 1.