FUEL VAPOR PURGE SYSTEM

A fuel vapor purge system includes: a fuel tank (10); a canister (13); a passage component (22) that defines an intake passage of an internal-combustion engine (2); a purge pump (14) pumping vapor fuel; and a valve device (15, 115, 215, 315) having a valve object (152), a main part (150) having an internal passage, an inflow port (154) through which the vapor fuel pumped from the canister flows into the main part, an outflow port (155) connected with the inflow port through the internal passage and being opened to the intake passage, and a leak port (4, 104, 204, 304) connected with the inflow port through the internal passage and being opened to outside of the main part. The leak port has a leak preventive structure (40, 221) which prevents the vapor fuel from leaking to outside when the valve device is attached to the passage component such that the vapor fuel is able to flow into the intake passage.