An object of the present invention is to provide a liposome and a liposome composition in which release of a drug in blood is suppressed during accumulation of the liposome and the liposome composition in a target site such as a tumor and the drug is rapidly removed after the liposome and the liposome composition are sufficiently accumulated. According to the present invention, there is provided a liposome containing at least a phospholipid to which a hydrophilic polymer is bonded, a phospholipid having a negative charge within a range of a pH of 6 to 8, and a phospholipid which is electrically neutral within a range of a pH of 6 to 8, in which an average carbon chain length of the phospholipid to which the above-described hydrophilic polymer is bonded is shorter than an average carbon chain length of the above-described phospholipid which is electrically neutral within a range of a pH of 6 to 8.
