Solid-state lighting device and illumination fixture using the same

[Summary] [Object] To provide a solid light source lighting device able to limit a range of an operation frequency of switching even when the dimming is performed in a wide range. [Means for Settlement] A direct-current power source circuit part 1 where an inductor L1 is connected in series to a switching element Q1 supplies a current to a solid light source 3 with use of charging and discharging currents of the inductor L1 or with use of any one of the currents. A current control part 2 includes: first switching control means adapted to vary an on-width of the switching element Q1; and second switching control means adapted to control an on-timing of the switching element Q1, and the second switching control means is able to vary a time from a zero cross of the discharging current of the inductor L1 to turning-on of the switching element Q1, sets the time to be substantially same time until the level of dimming reaches a predetermined level, and operates to direct the time to be longer after the level exceeds a predetermined level.