An image heating device for heating an image formed on a recording material (P), comprising: a heater , the heater includes, a substrate ; a first conductive element provided on the substrate along a longitudinal direction of the substrate ; a second conductive element provided on the substrate along the longitudinal direction at a position different from the first conductive element in a widthwise direction of the substrate ; and a heat generating resistor provided between the first conductive element and the second conductive element , and showing a positive temperature characteristic of resistance, which generates heat when power is supplied via the first conductive element and the second conductive element , characterized in that a plurality of heating blocks each of which includes a set of the first conductive element , the second conductive element , and the heat generating resistor is provided in the longitudinal direction, and power control of a heating block (302-1, 302-3) which is positioned remote from a conveyance reference position (X) is arranged to be performed independently of a heating block (302-2) which is positioned at a position including the conveyance reference position (X), and the device further comprises a first temperature detecting element (TH1) configured to detect a temperature of the heating block (302-2) which is positioned at the position including the conveyance reference position (X), a second temperature detecting element (TH2, TH3) configured to detect a temperature of the heating block (302-1, 302-3) which is positioned remote from the conveyance reference position (X), and a third temperature detecting element (TH4) configured to detect a temperature of, in the longitudinal direction of the substrate, an end portion of the heating block (302-2) which is positioned at the position including the conveyance reference position (X). a heater , the heater includes, a substrate ; a first conductive element provided on the substrate along a longitudinal direction of the substrate ; a second conductive element provided on the substrate along the longitudinal direction at a position different from the first conductive element in a widthwise direction of the substrate ; and a heat generating resistor provided between the first conductive element and the second conductive element , and showing a positive temperature characteristic of resistance, which generates heat when power is supplied via the first conductive element and the second conductive element , characterized in that a plurality of heating blocks each of which includes a set of the first conductive element , the second conductive element , and the heat generating resistor is provided in the longitudinal direction, and power control of a heating block (302-1, 302-3) which is positioned remote from a conveyance reference position (X) is arranged to be performed independently of a heating block (302-2) which is positioned at a position including the conveyance reference position (X), and the device further comprises a first temperature detecting element (TH1) configured to detect a temperature of the heating block (302-2) which is positioned at the position including the conveyance reference position (X), a second temperature detecting element (TH2, TH3) configured to detect a temperature of the heating block (302-1, 302-3) which is positioned remote from the conveyance reference position (X), and a third temperature detecting element (TH4) configured to detect a temperature of, in the longitudinal direction of the substrate, an end portion of the heating block (302-2) which is positioned at the position including the conveyance reference position (X). <EOS>