An all-in-one self test kit includes: a test tool having a reagent container adapted to store a diagnosis reagent therein and a diagnosis kit with a casing constituted of a first body and a second body and a diagnosis strip disposed inside the casing and having a sucking part for sucking the diagnosis reagent and a diagnosis part reacting to the diagnosis reagent sucked to the sucking part; a sub-body having a container insertion portion for inserting the reagent container thereinto and a kit insertion portion for inserting the diagnosis kit thereinto; a main body for inserting the sub-body thereinto; and a cap fastened and unfastened with an entrance of the main body to open and close the main body.