A liquid surface detector includes a terminal, a covering portion, and a sealing film. The terminal includes a ridge portion between a first wall face and a second wall face. The terminal sends an electric signal relating to detection of height of a liquid surface. The covering portion covers the terminal. The sealing film is formed between the terminal and the covering portion and is put into close contact with the terminal and the covering portion. The terminal further includes a groove and two second slant faces. The groove has a V-shape in cross-section and includes two first slant faces. The groove cuts off in the V-shape the ridge portion of an area of the first wall face covered with the sealing film. The two second slant faces respectively connect together an area of the second wall face covered with the sealing film and the two first slant faces. A boundary portion formed by contact between the two second slant faces which are opposed to each other is continuous with a top portion of the groove.