The invention discloses a machine button and a positioner. A button body is of a T-shaped column structure. The upper end and the lower end of the button body are provided with a plurality of longitudinal positioning holes and tack holes respectively. The tack holes are communicated with the positioning holes respectively. A plurality of transverse lock holes are formed in the column wall of the upper end of the button body. The lock holes are correspondingly communicated with the positioning holes respectively. A plurality of non-return rings are arranged in the lock holes. The positioner is composed of a base and a plurality of connection plugs. A guiding groove is formed between the bottom face of the column and the outer side column wall of each connection plug. When the connection plugs on the positioner are inserted into the positioning holes in the button body, the lock holes corresponding to the button body and the tack holes are in smooth communication with the guiding grooves in the connection plugs. A garment is placed on the lower end face of the button body, and a plurality of button tacks are inserted into the tack holes in the button body through the garment respectively; when the tack heads of the button tacks enter the lock holes under the guidance of the guiding grooves, the lock holes can lock the button tacks through the non-return rings, and therefore the button body is tacked to the garment.