Abstract: An illuminating apparatus using semiconductor light emitting elements comprising: n LED groups (n?2) which are serially connected, each being capable of radiating light in a half cycle of an AC input voltage and including a first LED of a first color temperature or a second LED of a second color temperature higher than the first color temperature, wherein, in a current flow path, a first LED group of the n LED groups includes the first LED; and a set of switches including at least one bypass switch located between the p-th LED group (1?p<n) and the (p+1)-th LED group in the current flow path for bypassing, in the ON position, a current flow to the (p+1)-th LED group, thereby enabling each of the n LED groups to radiate light in a certain interval of said half cycle.