A water purifier includes: a case including components; a cover mounted to the case to be opened and closed; a support frame mounted to the inside of the case and having at least one mounting part; a filter module detachably mounted to the case through the mounting part to filter and purify introduced raw water; a first flow path module including at least one flow path through which raw water flows and detachably mounted to the case between the case and the support frame to fix the filter module to the inside of the case; a second flow path module including at least one flow path through which purified water flows and which is connected to the components and the filter module, the second flow path module being detachably mounted to the case through the mounting part; and a faucet module mounted to the case to discharge purified water.