In a switch module which is arranged in opposition to a key substrate, the switch module is provided which is able to reduce an amount of light leaking out from the vicinity of an edge portion of a light reflection member in the direction of key parts, so that the key parts can be illuminated in a uniform manner by the light which advances in the interior of a light guiding member. A switch module (1) is provided with a circuit substrate (6) that has a metal dome sheet (4) mounted on a surface thereof which is arranged in opposition to a key substrate (8), a light guiding sheet (4) that is arranged between the key substrate (8) and the circuit substrate (6), an LED (2), and a reflector (9) that makes the light emitted from the LED (2) incident into the light guiding sheet (3) from an end thereof, wherein key parts (7) are able to be illuminated by the switch module 1. At an inner side of the reflector (9) in the light guiding sheet (3), there is formed a printed pattern (12) of white ink for scattering light on an optical path of the light which transmits through a first surface (3b) from the vicinity of an edge portion of the reflector (9).