1. An interpolation frame generation apparatus for generating an interpolation frame image to be inserted between continuous frame images, comprising: a motion vector detection module configured to execute block matching processing in each of a plurality of blocks included in the continuous frame images and specify one motion vector on an interpolation frame; and a generation module configured to, for an interpolation block in which the motion vector detection module specifies one motion vector, generate an interpolation frame image based on the motion vector, and for an interpolation block in which the motion vector detection module does not specify one motion vector, generate an interpolation frame image based on the frame image containing no motion vector component, wherein the motion vector detection module comprises: a first detection module configured to divide the frame image into a plurality of first blocks and execute block matching processing in each first block if it is impossible to specify one vector for which a difference between a minimum value and a minimal value of a Sum of Absolute Difference (SAD) value is not more than a predetermined value, determine that no motion vector is detected, and if it is possible to specify one vector for which the difference between the minimum value and the minimal value of the SAD value is not more than the predetermined value, determine that a motion vector is detected; a second detection module configured to, for a block in which the first detection module detects no motion vector, divide the frame image into second blocks larger than the first block and execute block matching processing in each second block if it is impossible to specify one vector for which the difference between the minimum value and the minimal value of the SAD value is not more than the predetermined value, determine that no motion vector in the second block is detected, and if it is possible to specify one vector for which the difference between the minimum value and the minimal value of the SAD value is not more than the predetermined value, select a motion vector of the second block; and a third detection module configured to, for a block in which the second detection module detects no motion vector, divide the frame image into third blocks larger than the second block and execute block matching processing in each third block if it is impossible to specify one vector for which the difference between the minimum value and the minimal value of the SAD value is not more than the predetermined value, determine that no motion vector in the third block is detected, and if it is possible to specify one vector for which the difference between the minimum value and the minimal value of the SAD value is not more than the predetermined value, select a motion vector of the third block.