To provide a safety device of a battery temperature control system for an EV or an HEV capable of preventing an electric shock due to the electrical conduction across terminals of batteries in the event of a vehicle collision.A safety device used in a temperature control system of a battery for a vehicle, including a first heat exchange unit (1) which includes a first heat exchange section (2) filled with a liquid-state heat medium into a pipe (3) and exchanging heat with a battery (B) by the heat medium, and a second heat exchange unit (20) which includes a second heat exchange section (21) heating or cooling the heat medium subjected to heat exchange in the first heat exchange section (2), wherein the heat medium existing in the first heat exchange section is discharged to the outside of the first heat exchange section, for example, under a predetermined condition such as a vehicle collision.