According to a photocatalyst-based air purification module detachably attached to a ceiling type lamp having a light source of a side light tube of the present invention, the air purification module detachably attached to a light source unit of a ceiling type lamp comprises: a light source unit which uses power to emit light in a predetermined wavelength (or wavelength band) and has a structure of a cylindrical light tube； a socket unit which inserts the light source unit from a side, supports the same and supplies power to the light source unit； a reflector unit which guides light emitted through the light source unit inserted to the socket unit to a predetermined range and has an upper area thereof closed； and a frame unit which has a structure coupling to at least one between the socket unit and the reflector unit to be fixed to a ceiling. The present invention comprises: an attachment structure unit which has an attachment area capable of attachment in a designated geometric structure to a designated light tube area of the light tube structure light source unit inserted from a side to the socket unit, and maintains a state attached to the designated light tube area of the light tube structure light source unit by means of a structural characteristic of the attachment area and the friction； a photocatalyst matter unit which is formed by coating a designated photocatalyst matter on a designated air contacting area among areas of the attachment structure unit or by coating a designated photocatalyst matter on a designated air contacting areas among areas of a contact structure unit provided for being in contact with air in at least one side area of the attachment structure unit； a generation unit which is provided in or bound to one side of the attachment structure unit attached to the designated light tube area of the light source unit, and receives light emitted from the light source unit to generate designated power； and a fan unit which operates based on the po
