A light-emitting element driving device includes a setter and first to nth constant current sources. An ith series circuit is a series circuit of an ith light-emitting element string and the ith constant current source. The ith constant current source is turned on and off with a delay from an ith dimming signal indicating either lighting or extinction of the ith light-emitting element string. The setter has a mode in which it sets the target value of an output voltage fed to the respective anodes of the first to nth series circuits at a value at which the jth light-emitting element string can be lit during the period from a first time point that a jth dimming signal switches from indicating extinction of the jth light-emitting element string to indicating its lighting to a second time point that the jth constant current source switches from off to on.