To provide an auxiliary turn signal lamp which can perform high-visibility directional sign on the rear surface side of a rear glass, and also has a function of an emergency flashing indicator.

A pair of right and left clusters of illuminators which can flash are arranged on the rear surface side of the rear glass P of the rear of a vehicle. The cluster of illuminators are constructed of a plurality of LED illuminators (Li, Ri) adjacent to each other in the right and left directions. Then second illuminators (L2, R2) are lit after a predetermined time delay from the lighting of first illuminators (L1, R1) positioned on the inner side of each of the clusters of illuminators at the time of directional sign. Then all of the other illuminators (Lx, Rx) positioned on the outer side are lit linearly one by one.