A continuous positive airway pressure (CPAP) apparatus includes: a first unit including a first housing provided with a first flow path that connects a first inlet port and a first outlet port and in which an air blower is provided; and a second unit including a second housing provided with a second flow path that connects a second inlet port and a second outlet port. The first flow path between the first inlet port and the air blower includes a first silencer. The second flow path includes a second silencer. In a first use state where the second unit is attached to the first unit, the second outlet port is connected to the first inlet port. In a second use state where the second unit is not attached to the first unit, the first inlet port is opened to the outside.