A collision detection device for a vehicle includes a first direction signal outputting unit which detects an intensity of heat ray radiated from a detection object which is near or contacts the vehicle to outputs a first direction signal, a second direction signal outputting unit which detects ultrasound wave sent by a sending member and reflected by the detection object to output a second direction signal, an impact signal outputting unit which detects an impact on the vehicle to output an impact signal, and a control unit. The control unit determines an occurrence of a collision between the vehicle and a human, in the case where it is determined that a difference between the first direction signal and the second direction signal is within a first predetermined range and the impact signal is outputted.