A lithographic printing plate precursor which is capable of being on-machine developed by supplying at least one of an ink and a fountain solution and comprises a hydrophilic support having provided thereon an image-forming layer containing the following components (1) to (3), wherein the image-forming layer further contains a filler: (1) an infrared absorbing agent; (2) a compound capable of generating an acid or a radical; and (3) a compound capable of undergoing addition polymerization with the acid or radical.