To provide a self-propelled work robot in which a plurality of kinds of work assemblies can be easily interchanged and which can deal with various kinds of work for a floor surface by only one.

This self-propelled work robot is equipped with a propelling assembly 1 with wheels 6 and first and second work assemblies 20, 50 detachably attached on the propelling assembly 1. Only one of either first or second work assembly 20, 50 is selectively mounted on the propelling assembly 1. Work assemblies 20, 50 are equipped with an assorting means 33 to enable the kind of work assemblies to be assorted, respectively. The propelling assembly 1 is equipped with a drive motor 5 to drive wheels 6, a propelling wheel control means 41 to control rotation of the drive motor 5, a discriminating means 38 to discriminate which of both work assemblies 20, 50 is mounted, and a drive signal output means 39 to output work signals to actuate the work assemblies 20, 50 corresponding to a result of the discrimination.