A push-button switch comprising: a plunger that includes a push-button that is made of a light-transmitting material; a lever linking mechanism that translates the plunger; and a switch main body that is operated together with a pressing action of the plunger, the plunger, the lever linking mechanism, and the switch main body being mounted to a base, the lever linking mechanism comprising: a pair of lever links (11a and 11b) that are disposed on the base so as to be abutted so as to be pivotable around an intermediate pivoting point; and joint members (12a and 12b) that link abutted end portions of the lever links (11 a and 11 b) to each other, the lever links (11 a and 11b) being operable by the plunger, an operating segment that faces the switch main body being disposed so as to span the lever links (11a and 11b), and the lever links (11a and 11b) being forced by springs (13a and 13b) that are engaged in outer end portions of the lever links (11 a and 11 b) so as to be pulled toward each other to enable the lever linking mechanism to perform a snap action in a direction of movement of the plunger together with a pivoting operation of the lever links (11 a and 11b) that accompanies displacement of the plunger, the switch main body being configured so as to be pressed and operated by the operating segment that moves in the direction of movement of the plunger together with the action of the lever linking mechanism, and a flat illuminating portion that illuminates the push-button from behind being mounted so as to be able to move integrally with the plunger, wherein: a mark for conveying information to a user is disposed on a portion of the push-button; the illuminating portion comprises: a light-guiding plate that is disposed between the switch main body and the push-button; and a mark light source portion; a mark diffusing portion that diffuses injected light is disposed on a portion of the light-guiding plate that faces the mark; and light is injected into the light-guiding plate from the mark light source portion so as to be directed toward the mark diffusing portion, characterized in that the illuminating portion further comprises a main light source portion that injects light into the light-guiding plate, and a main diffusing portion that diffuses the light that is injected by the main light source portion is disposed on the light-guiding plate. a plunger that includes a push-button that is made of a light-transmitting material; a lever linking mechanism that translates the plunger; and a switch main body that is operated together with a pressing action of the plunger, the plunger, the lever linking mechanism, and the switch main body being mounted to a base, the lever linking mechanism comprising: a pair of lever links (11a and 11b) that are disposed on the base so as to be abutted so as to be pivotable around an intermediate pivoting point; and joint members (12a and 12b) that link abutted end portions of the lever links (11 a and 11 b) to each other, the lever links (11 a and 11b) being operable by the plunger, a pair of lever links (11a and 11b) that are disposed on the base so as to be abutted so as to be pivotable around an intermediate pivoting point; and joint members (12a and 12b) that link abutted end portions of the lever links (11 a and 11 b) to each other, an operating segment that faces the switch main body being disposed so as to span the lever links (11a and 11b), and the lever links (11a and 11b) being forced by springs (13a and 13b) that are engaged in outer end portions of the lever links (11 a and 11 b) so as to be pulled toward each other to enable the lever linking mechanism to perform a snap action in a direction of movement of the plunger together with a pivoting operation of the lever links (11 a and 11b) that accompanies displacement of the plunger, the switch main body being configured so as to be pressed and operated by the operating segment that moves in the direction of movement of the plunger together with the action of the lever linking mechanism, and a flat illuminating portion that illuminates the push-button from behind being mounted so as to be able to move integrally with the plunger, wherein: a mark for conveying information to a user is disposed on a portion of the push-button; the illuminating portion comprises: a light-guiding plate that is disposed between the switch main body and the push-button; and a mark light source portion; a mark diffusing portion that diffuses injected light is disposed on a portion of the light-guiding plate that faces the mark; and light is injected into the light-guiding plate from the mark light source portion so as to be directed toward the mark diffusing portion, a mark for conveying information to a user is disposed on a portion of the push-button; the illuminating portion comprises: a light-guiding plate that is disposed between the switch main body and the push-button; and a mark light source portion; a light-guiding plate that is disposed between the switch main body and the push-button; and a mark light source portion; a mark diffusing portion that diffuses injected light is disposed on a portion of the light-guiding plate that faces the mark; and light is injected into the light-guiding plate from the mark light source portion so as to be directed toward the mark diffusing portion, the illuminating portion further comprises a main light source portion that injects light into the light-guiding plate, and a main diffusing portion that diffuses the light that is injected by the main light source portion is disposed on the light-guiding plate.