PURPOSE: To perform switch on/off of a light and to remove the light from a moving body without a part, such as a wheel, of a bicycle forming a constitut ing requirement.

CONSTITUTION: A battery type light comprises a running detecting part 2 to detect vibration during running of a moving body, such as a bicycle, by means of a vibration sensor 1 and output a detecting signal indicating running of the moving body based on the output of the vibration sensor 1; a lightness detecting part 5 to output a detecting signal when ambient brightness is reduced to specified brightness or less, based on the output of a photo sensor 4 to detect ambient brightness; and a lamp control part 3 to effect control of connection between a battery 7 and the bulb 10 to light ON a bulb 10. Further, a timer circuit 8 to measure a specified time starting from the stop of running of the moving body is additionally provided. After the specified time is measured by the timer circuit 8 after the stop of a detecting signal from the running detecting part 2, disconnection between the battery 7 and the bulb 10 is controlled. The constitution members are contained in one casing, which is mounted on and demounted form the moving body.