To provide a connection type hot water supply device having no inconveniences while reducing cost, the number of parts and power energy.

External solenoid valves conventionally mounted between each of water heaters and a common hot water supply passage are omitted and substituted by a can water amount control valve and a bypass valve built in each of the water heaters with completely water stopping function. The can water amount control valve and the bypass valve of each of a main water heater and a sub water heater are both fully opened within ten minutes after previous operation SWOFF to allow draining operation for antifreezing (YES in S1, S2, NO in S4). After the lapse of ten minutes, the bypass valve is open and the can water amount control valve is closed only for the main water heater so as to allow water supply with non-combustion when hot water cock is opened (NO in S1, S3). When MOQ or more is detected with operation SWON, the combustion of the main water heater is allowed but the combustion of the sub water heater is prohibited (YES in S4, YES in S6, S7). The can water amount control valve and the bypass valve of the sub water heater are both fully closed (S8).