A respiratory assistance device includes a gas supply source, an inspiratory pipe, and a humidifier. A gas is supplied to a mask through the gas supply source and the inspiratory pipe. The humidifier includes a liquid supply unit, a humidifying member, a holder unit and a heating unit. The liquid supply unit supplies a liquid to the humidifying member. The humidifying member has an aspect that makes one round of the inner periphery of the inspiratory pipe, and vaporizes the liquid supplied from the liquid supply unit. The holder unit holds the humidifying member such that the humidifying member is disposed to make one round of the inner periphery of the inspiratory pipe in a continuous or discontinuous manner. The heating unit heats the inside of the inspiratory pipe.
