A canister device includes a main canister, a sub-canister, and a hose. The main canister includes a charging port, a purging port, and a main canister-side connection port. The sub-canister is separated from the main canister and located on a side of the main canister, and includes a drain port opened to the atmosphere and disposed on the same side as the main canister-side connection port of the main canister and a sub-canister side connection port disposed on the opposite side from the drain port. The hose provides fluid communication between the main canister-side connection port and the sub-canister-side connection port.