Hello, if it is not the landlord himself, it depends on whether the contractor has the right to dispose of the house and whether it is authorized by the owner. If you have the authorization of the owner of the house, it is effective to conclude a contract within the scope of authorization. However, if it does not belong to the above two situations, the subject who signed the contract does not have the right to dispose of it, which constitutes an unauthorized agency and the validity of the contract is to be determined. Unless the owner of the house, that is, the landlord, approves the behavior of the actual contractor, the contract is valid.

Legal basis:

Article 48 of the Contract Law: A contract concluded in the name of the principal without the agent's authorization, beyond the agent's authorization or after the termination of the agent's authorization is invalid for the principal, and the actor shall bear the responsibility.

The other party may urge the principal to ratify it within one month. If the trustor fails to declare it, it shall be deemed as refusal to ratify it. Before the contract is ratified, the bona fide counterpart has the right to cancel the contract. Revocation shall be made by notice.