Notification device and signal display light

A notification device including a signal unit for transmitting predetermined signal and an acoustic unit connected with the signal unit for notifying sound to a front side, wherein

• the acoustic unit includes:
• a sound source;
• and
• a main body case including an upper main wall extending longitudinally and laterally, a lower main wall extending longitudinally and laterally and opposing the upper main wall from a lower side, and an output opening for outputting sound from the sound source to an opposing space between the upper main wall and the lower main wall from an upper side, wherein
• the main body case includes:
• a front main wall provided at a front side of the output opening and bridged between the upper main wall and the lower main wall, the front main wall for preventing entering of a water droplet to the output opening from a front side and for guiding sound outputted from the output opening to a rear side;
• and
• a rear main wall extending vertically and laterally and opposing to an output opening side of the front main wall from a rear side with an interval, the rear main wall for reflecting sound outputted from the output opening to a front side, wherein
• a first space between the front main wall and the rear main wall, a second space surrounded by a left surface of the front main wall and the rear main wall and the upper main wall and the lower main wall, and a third space surrounded by a right surface of the front main wall and the rear main wall and the upper main wall and the lower main wall are communicating with one another along a crosswise direction at a rear end part of each of the first space, the second space and the third space.