The invention discloses a lamp. The lamp comprises a lamp housing, two installation plates, two contact discs, two rotary discs, a reflector, four lamp holders, two lamp tubes and a fixing mechanism, wherein three pairs of electrode holders are arranged on the first surface of each contact disc, the two contact discs are respectively fixedly connected with the corresponding installation plate, the two rotary discs are respectively connected with the corresponding contact disc in a rotary mode, the reflector is formed by connecting four reflecting surfaces in an end-to-end mode, the two ends of the reflector are fixedly connected with the two rotary discs, the four lamp holders are fixed to the rotary discs respectively and are divided into two pairs, the two lamp holders of each pair are oppositely arranged on and fixed to the two rotary discs respectively, the two ends of each lamp tube are connected with the corresponding pair of lamp holders, when the rotary discs rotate, the pair of lamp holders which are originally in contact with the electrode holders on the contact discs are disconnected with the corresponding electrode holders, and contact pins of the other group of lamp holders are in contact with the electrode holders on the contact discs. According to the lamp, the lamp tubes are both installed on the lamp and are driven through rotation of the rotary discs to rotate, and in this way, when the lamp tubes need to be replaced, troublesome operation of lamp tube storage and direct replacement of the lamp tubes is avoided.