According to a photocatalyst module held in a ceiling type lamp having a light source in the form of a downward light bulb of the present invention, the photocatalyst module detachably held in 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 an appearance of a light bulb； a socket unit which inserts the light source unit from a bottom, supports the same and supplies power to the light source unit； and a frame unit which has a structure coupling to the socket unit to be fixed on a ceiling. The present invention comprises: a holding structure unit which has a holding area capable of holding in a designated geometric structure in a designated light bulb area corresponding to an area between a minimum diameter and a maximum diameter based on a circular cross section of the light bulb form light source unit which is a light bulb shape inserted from a bottom to the socket unit, and maintains a state held in the designated light bulb area of the light bulb form light source unit by means of a relationship between a structural characteristics of the holding area and the gravity of the Earth； and a photocatalyst matter unit which is formed by coating a designated photocatalyst matter on a designated air contacting area among areas of the holding 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 holding structure unit. Accordingly, the present invention purifies air in a space where the ceiling type lamp is provided while the ceiling type lamp is used.COPYRIGHT KIPO 2020본 발명의 하향식 전구 형태 광원을 구비한 천정형 전등에 거치되는 광촉매모듈에 따르면, 전원을 이용하여 지정된 파장(또는 파장 대역)의 빛을 발광하며 전구 형태의 외형을 지닌 광원부와, 아래 방향에서 상기 광원부를 삽입하여 지지하며 상기 광원부에 전원을 공급하는 소켓부와, 상기 소켓부와 결합되어 천정에 고정되는 구조를 지닌 프레임부를 구비한 천정형 전등의 광원부에 탈거치 가능한 광촉매모듈에 있어서, 상기 소켓부에 아래 방향
