A control valve includes a valve housing, a joint member, a valve body, and a sealing tube member. The sealing tube member has a biasing pressure receiving surface that receives a pressure of a liquid inside the valve housing and biases the sealing tube member to the valve body side. An area S1 of the biasing pressure receiving surface and an area S2 of a valve sliding contact surface of the sealing tube member are set to satisfy Expressions (1) and (2),
S1<S2≤S1/k   (1)
α≤k<1   (2) where k is a pressure reduction constant of a liquid flowing through a minute gap between the valve sliding contact surface and the valve body, and α is a lower limit value for the pressure reduction constant determined based on physical properties of a liquid.

A control valve includes a valve housing, a joint member, a valve body, and a sealing tube member. The sealing tube member has a biasing pressure receiving surface that receives a pressure of a liquid inside the valve housing and biases the sealing tube member to the valve body side. An area S1 of the biasing pressure receiving surface and an area S2 of a valve sliding contact surface of the sealing tube member are set to satisfy Expressions (1) and (2),

S1<S2S1/k (1)

k<1 (2) where k is a pressure reduction constant of a liquid flowing through a minute gap between the valve sliding contact surface and the valve body, and is a lower limit value for the pressure reduction constant determined based on physical properties of a liquid.