A master cylinder for a vehicle is provided to prevent damage to a seal due to reverse current after the operation of TCS or ESC with providing economic machining processes. A master cylinder for a vehicle comprises: a housing(110) in which a liquid pressure chamber is formed in order to contain oil inside; a piston(120) inserted into the liquid pressure chamber; a plurality of inlet ports(130) which are installed at the housing and supply the oil to the liquid pressure chamber; and a plurality of seals opening and closing an oil route according to the contact with a piston(140). The piston controls the pressure of the liquid pressure chamber with reciprocation. The seal is fixed to a plurality of grooves formed on the inner surface of the housing. The oil route is formed through the space formed between the piston and the seal.
