Disclosures of the present invention describe a phototherapy device mainly comprises a phototherapeutic host and a patch module having a connection base, wherein the patch module can be assembled with the phototherapeutic host by letting the connection base be connected with the base through an interlocking mechanism, a rotary locking mechanism or a magnetic lock mechanism. In addition, the phototherapeutic host can be attached to and detached from the patch module. Briefly speaking, this phototherapy device has advantages of simple structure, small volume, being portable, being easy to be operated, and having patch units that are replaceable. In addition, the phototherapeutic host is designed to have a modular structure comprising a base, a PCB, a lighting unit, and a cover, such that the phototherapeutic host can be manufactured and/or used individually.
