PURPOSE: To facilitate switching of red and blue or yellow to smoothen traffic control.

CONSTITUTION: A worke site lamp for traffic control comprises a cylindrical main body 2 constituted of a display 4 having red portions 6 and blue portions 7 arranged alternately at the same width and a grip 5, and a cylindrical outer cylinder 11 having transparent portions 12 and opaque portions 13 arranged alternately at the same width as the red and blue portions 6, 7 and slidably fitted around the display 4. When the outer cylinder 11 is slid, the transparent portions 12 of the outer cylinder 11 mate with either the red portions 6 or the blue portions 7 in the display 4 of the main body, thus displaying that color.