A vehicle indoor illumination device includes a housing having an upper opening with an internal space formed therein, a light-emitting unit disposed on the housing to emit light, a diffuser disposed outside the light-emitting unit in a manner as to close the upper opening of the housing to allow the light emitted from the light-emitting unit to diffuse to the outside, a cover part disposed on an outer surface of the diffuser and on which a light pattern is formed through scattering of the light transmitted through the diffuser, and a controller configured to receive an operation signal of a vehicle electronic part to control an operation of the light-emitting unit.