Constant-temperature and instant-heating type shower device

The invention provides a constant-temperature and instant-heating type shower device which comprises an outer shell, a power circuit, a temperature setting switching circuit, an automatic power control circuit and heating circuits. The output end of the power circuit is connected with the input end of the temperature setting switching circuit, and the output end of the temperature setting switching circuit is connected with the input end of the automatic power control circuit. The heating circuits comprise the first heating circuit and the second heating circuit. The first heating circuit comprises a normally-open contact of a first relay and a first heating component. The second heating circuit comprises a second heating component and a first bidirectional silicon controlled rectifier which are connected in series. The constant-temperature and instant-heating type shower device further comprises a first temperature measurement device and a water flow switch. The water flow switch and a coil of the first relay are connected to the power circuit, the first temperature measurement device is arranged at the second heating component, and the output end of the automatic power control circuit is connected with the control pole of the first bidirectional silicon controlled rectifier. The constant-temperature and instant-heating type shower device can guarantee that the output water temperature will not change along with change of the water flow and high temperature will not be generated in the process of restarting after short-time halt, and the device is convenient to use.