make an air blowing system of the gas heater portion 3 and that of the electric heater portion 4 independent of each other the gas heater portion 3 comprises a gas burner 30 serving as a combustion heater and a first air blowing fan 31 which is arranged below the gas burner 30 and which supplies the gas burner 30 with combustion air and mixes combustion gas from this gas burner 30 with air sucked through the first inlet 13 a in the frame 11 to blast them out to a room the gas burner 30 is an all primary air burner and has a burner body 30 a in which there are formed a fuel air inlet 301 faced by a gas nozzle not shown mounted to a tip of a gas tube connected with an electromagnetic safety valve and a proportional control valve not shown which are arranged in the frame 11 and a mixer tube portion 302 communicating with this inlet 301 on an open upper face of the burner body 30 a a ceramic combustion plate 303 having a plurality of flame ports provided therein in a row is mounted via a distribution plate not shown this gas burner 30 is contained in a combustion frame 304 in the frame 11 there is also provided a diversion plate 51 in such a manner as to surround an upper side of the combustion chamber 304 and so that when 1 first air blowing fan 31 described later is operated air sucked through the first inlet 13 a in the frame 11 and combustion gas from the combustion chamber 304 may be partitioned from each other until they flow by a predetermined distance in the frame 11 there is provided a.