The present invention relates to a polyester for a toner, obtained by polycondensing an alcohol component and a carboxylic acid component containing an alkylsuccinic acid having 10 or more carbon atoms, an alkenylsuccinic acid having 10 or more carbon atoms, or a mixture thereof, in an amount of from 0.5 to 50% by mole, wherein each of 6-methyl-2-heptanone and 5-methyl-2-heptanone is detected in an amount of 0.5 ppm or less as determined by thermal desorption-gas chromatography-mass spectrometry. The polyester for a toner of the present invention is used as a resin binder, or the like, for a toner used, for example, for developing electrostatic latent images formed in electrophotography, electrostatic recording method, electrostatic printing method, or the like.