A fuel consumption saving control device for a work vehicle includes: a vehicle speed detector 11 for detecting whether the vehicle is traveling; an accelerator operation detector 16 for detecting whether an accelerator operating member is not operated; a boom operating lever 23 for detecting whether a command to carry out operation to lift a boom which performs cargo carrying work has been issued; and a controller 8 for carrying out control for increasing a speed reducing ratio of a travel transmission 4 when the vehicle speed detector 11 detects that the vehicle is traveling, the accelerator operation detector 16 detects that the accelerator operating member is not operated, and also the boom operating lever 23 detects that the command to lift the boom has been issued.