A frame of an electric cart includes a front part, and a rear part separable from the front part; the front part has a locating member secured on a rear end thereof; the rear part has a connecting member secured on a front end thereof for engaging the locating member, which connecting member has a spring-loaded engaging pin passed through it; the pin is made such as to be capable of engaging the locating member automatically while the rear part is being moved so as to fit the connecting member onto the locating member, thus securely joining the rear part to the front part; the engaging pin will be disengaged from the fitting portion when it is pressed at a first end, thus allowing the rear part to be separated from the front part.