To improve startability by precisely controlling starting mixture and to improve hot startabiilty of an engine by improving a heat insulation characteristic of a temperature-sensitive driving body.

This automatic starting device comprises a starting device body B and a cover holder J. The starting device body B comprises integrally formed wax holder F for storing the temperature-sensitive driving body C, a starting valve V, and a valve body G having a starting air passage 11, a starting mixture passage 12, and a starting fuel passage 10. The cover holder J has terminals T1 and T2 electrically connected to a heater 13. A valve body G of the starting device body B is inserted into and disposed in a valve body insert recessed part A1 in a base body A, the upper bottom J1 of the cover holder J is brought into contact with a collar K of the wax holder F through the heater 13 held by the terminals T1 and T2, and a cylindrical part J2 of the cover holder forms an annular interior part P in a substantially closed shape on the outer periphery of the wax holder F.