Hot water supply device and hot water supply system

A hot water supply device (10) is provided with: a first device (for example, a bathroom remote controller (13)) for performing control relating to hot water supply; a second device (for example, a water heater (11)) that is communicably connected to the first device and performs control relating to hot water supply; and a communication unit that is provided in the first device and can be connected to an external communication network. The first device divides data of control software of the second device acquired from an external device (for example, a server (50)) via the communication unit, into a plurality of parts, and transmits the same to the second device. 热水供给装置(10)包括：第一设备(例如，浴室遥控器(13))，进行与热水供给相关的控制；第二设备(例如，热水供给器(11))，以能够通信的方式连接于第一设备，并进行与热水供给相关的控制；以及通信部，设置于第一设备，且能够与外部通信网连接。第一设备将经由通信部从外部装置(例如，服务器(50))获取的第二设备的控制软件的数据分割成多个，并发送至第二设备。