Provided are a novel europium compound which has a melting point of 180° C. or lower and can be stably supplied by bubbling in a chemical vapor deposition method or an atomic layer deposition method, a precursor for forming a europium-containing thin film based on the compound, and a method for forming a europium-containing thin film using this precursor. A europium-containing thin film is formed using bis(tetramethylmonoalkylcyclopentadienyl)europium as a precursor for forming a europium-containing thin film by a chemical vapor deposition method or anatomic layer deposition method.