NOVELTY - A radiation detection apparatus comprises a detector unit (30) having semiconductor radiation detection elements (12), a detector unit holding member having connector portions (6a, 22), and a positioning device having a coupling member (20) that attaches the detector holding member to the detector unit holding member.    USE - The invention is used for, e.g. radiological imaging apparatus (claimed) such single photon emission tomography apparatus, or positron emission tomography apparatus.    ADVANTAGE - The invention improves the arrangement density of semiconductor radiation detection elements.    DETAILED DESCRIPTION - A radiation detection apparatus comprises:    (1) a detector unit having semiconductor radiation detection elements each having a semiconductor area that interacts with radiation to generate charges and an anode and a cathode constructed opposite each other and across the semiconductor area, and a detector holding member in which these semiconductor radiation detection elements are installed in a matrix including rows in a direction a and rows in another direction b crossing the direction a;    (2) a detector unit holding member in which the detector units are installed, where the detector holding member is provided with anode signal lines arranged for every rows in the direction a and connected to the respective anodes of the semiconductor radiation detection elements belonging to the corresponding rows in the direction a and cathode signal lines arranged for every rows in the direction b and connected to the respective cathodes of the semiconductor radiation detection elements belonging to the corresponding rows in the direction a; the detector holding member is provided with a first connector portion to which the anode signal lines and the cathode signal lines are separately connected, the detector unit holding member is provided with a second connector portion releasably connected to the first connector portion; and    (3) a positioning device that positions a coupling member that releasably attached the detector holding member to the detector unit holding member, in a part of the detector holding member in which the first connector portion is not located, and in a part of the detector unit holding member in which the second connector portion is not located.    DESCRIPTION OF DRAWING(S) - The figure shows a perspective view of the radiation detection apparatus.    Connector portions (6a, 22)    Semiconductor radiation detection elements (12)    Coupling member (20)    Detection unit (30)