A decolorizing apparatus includes first and second heating units, first and second heat source units, and a controller. The first and second heating units decolorize an image using decolorable colorants which are decolorized if heated. The first heating unit heats one surface of a sheet. The second heating unit heats a remaining surface which is opposite to the one surface of the sheet heated by the first heating unit. The first heat source unit heats the first heating unit. The second heat source unit heats the second heating unit. The controller includes a first mode and a second mode. In the first mode, the controller performs a decolorizing process on both the surfaces of the sheet by heating the first and second heating units using the first and second heat source units. In the second mode, the controller performs the decolorizing process on one surface of the sheet by heating the first heating unit using the first heat source unit, and heats the second heating unit using the second heat source unit with output which is lower than output acquired in the first mode.