A manually operable sweeping-type compact printer apparatus includes a key entry unit, a display unit, a memory unit, an encoder and a printer unit which are mounted on a manually manipulatable housing. When the housing is manually moved over a printing medium with the printer unit in contact with the printing medium, data entered by the key entry unit is printed out on the printing medium. In the printer apparatus, only designated segments or lengths of data are printed out on the printing medium, independent of continued travel or movement of the housing. Also, even if the housing is moved over the printing medium at an unstable moving velocity, high printing quality can be realized by control of the printing head. Stop codes designating the end of a data segment can be automatically or manually inserted.