A solid light source lighting device comprising: a direct-current power source circuit part having an inductor comprising a primary winding and a secondary winding, the secondary winding being connected in series to a switching element for performing a power conversion to an input direct-current power source (Vdc) by means of the inductor and the switching element; and supplying a current to a solid light source by means of charging and discharging currents of the inductor; a current control part including a controlling integrated circuit for controlling the switching element so as to dim a current flowing to the solid light source; the controlling integrated circuit having a gate drive terminal outputting a gate drive signal of High/Low for controlling the switching element to be on/off; the controlling integrated circuit having a zero cross detection terminal for controlling the switching element to be on when detecting disappearance of a voltage of the secondary winding of the inductor; and the controlling integrated circuit having a peak current setting terminal (Ip) and being adapted to set a predetermined current threshold value (Ip1, Ip2, Ip3) depending on a dimming signal (Vdim) supplied from a dimmer to the peak current setting terminal (Ip); wherein a first switching control means is provided by the controlling integrated circuit adapted to vary an on-width of the switching element until the current reaches the predetermined current threshold value (Ip1,Ip2,Ip3); characterized by: the secondary winding of the inductor being connected with the zero cross detection terminal of the controlling integrated circuit via a diode; a timer circuit and a further diode being connected between the gate drive terminal and the zero cross detection terminal, so that the diodes (D2, D3) constitute an OR circuit; and wherein a second switching control means is provided by the timer circuit adapted to control an on-timing of the switching element; wherein the second switching control means is adapted to vary a time from a zero cross of the discharging current of the inductor until turning-on of the switching element, the second switching control means is adapted to set the time to be substantially same time until the level of dimming reaches a predetermined level, and the second switching control means is adapted to operate to direct the time to be longer after the level exceeds the predetermined level; and wherein the timer circuit limits the maximum value of the on-off frequency of the switching element by either limiting the minimum value of a on-off period or by limiting the minimum value of the off time of the switching element. a direct-current power source circuit part having an inductor comprising a primary winding and a secondary winding, the secondary winding being connected in series to a switching element for performing a power conversion to an input direct-current power source (Vdc) by means of the inductor and the switching element; and supplying a current to a solid light source by means of charging and discharging currents of the inductor; a current control part including a controlling integrated circuit for controlling the switching element so as to dim a current flowing to the solid light source; the controlling integrated circuit having a gate drive terminal outputting a gate drive signal of High/Low for controlling the switching element to be on/off; the controlling integrated circuit having a zero cross detection terminal for controlling the switching element to be on when detecting disappearance of a voltage of the secondary winding of the inductor; and the controlling integrated circuit having a peak current setting terminal (Ip) and being adapted to set a predetermined current threshold value (Ip1, Ip2, Ip3) depending on a dimming signal (Vdim) supplied from a dimmer to the peak current setting terminal (Ip); wherein a first switching control means is provided by the controlling integrated circuit adapted to vary an on-width of the switching element until the current reaches the predetermined current threshold value (Ip1,Ip2,Ip3); the secondary winding of the inductor being connected with the zero cross detection terminal of the controlling integrated circuit via a diode; a timer circuit and a further diode being connected between the gate drive terminal and the zero cross detection terminal, so that the diodes (D2, D3) constitute an OR circuit; and wherein a second switching control means is provided by the timer circuit adapted to control an on-timing of the switching element; wherein the second switching control means is adapted to vary a time from a zero cross of the discharging current of the inductor until turning-on of the switching element, the second switching control means is adapted to set the time to be substantially same time until the level of dimming reaches a predetermined level, and the second switching control means is adapted to operate to direct the time to be longer after the level exceeds the predetermined level; and wherein the timer circuit limits the maximum value of the on-off frequency of the switching element by either limiting the minimum value of a on-off period or by limiting the minimum value of the off time of the switching element.