A musical apparatus which outputs music under the control of various musical control instructions where the desired musical control instructions are reliably determined by the movement of an object in an operation space, and where the musical control instructions are varied by changing the state of motion of the object in space. The musical apparatus performs musical control instructions whose contents are based on the state of motion of an object in motion within a specified operation space. The musical apparatus may have at least one light source which shines light into said operation space, at least one light sensor which receives light which has been reflected by an object in the space so that it has at least two light paths which reach from the light source to the light sensor via the object, so that a detection values is output according to the quantity of light received via a respective one of the light paths, and a musical controller which outputs music and controls a musical function when the correlation between the current values of the detection values of the various paths satisfies a specified relationship.