PROBLEM TO BE SOLVED: To provide a controller of a turn indicator light and a turn indicator which can accurately detect disconnection and a short circuit even when a light source of the turn indicator light is replaced by a light source with largely different drive current.SOLUTION: A controller of a turn indicator light comprises: first drive means 20 for supplying first current to a light source 10; second drive means 40 which is connected in parallel with the first drive means 20 and for supplying second current smaller than the first current to the light source 10; and control means 90 for adjusting current to be supplied to the light source 10 by switching between the first drive means 20 and the second drive means 40. Here, the first drive means 20 has first detection means 30 for detecting disconnection of the light source 10 based on the first current, and the second driving means 40 has second detection means 50 for detecting the disconnection of the light source 10 based on the second current.
