Provided are a char feeding hopper that makes it possible to accurately measure char, a char recovery system, and a coal gasification combined power generation system. The char feeding hopper comprises: a char feeding hopper body that feeds separated char to a coal gasifier side; at least two casing tubes (121, 122) that are inserted from a side wall of the char feeding hopper body and that are provided so as to be aligned with one another in the vertical axis direction; a radiation source section (101) that is provided within the casing tube (121) and that emits γ-rays within the char feeding hopper body; and a γ-ray detector that is provided within the casing tube (122) and that detects emitted γ-rays. The cross-section of each casing tube (121, 122) has a shape that is provided with a tapered section (200) having an apex angle on the upper edge thereof.