A diagnostic imaging catheter comprising: a sheath configured to be inserted into a living body; a drive shaft rotatable in the sheath; and an imaging core portion attached to the drive shaft in the sheath, wherein the imaging core portion includes: a transmission and reception member capable of transmitting and receiving a signal; and a housing holding the transmission and reception member, wherein a side surface of the housing that faces a radial direction of the sheath includes an inclined portion that is inclined to approach a central axis line of the drive shaft toward a distal side until reaching a distal end, wherein the inclined portion extends from a proximal side of a distal end (11a2) of the transmission and reception member to a distal side of the distal end (11a2) of the transmission and reception member, wherein the transmission and reception member are an ultrasound transducer capable of transmitting and receiving ultrasound on a ultrasound transmission and reception surface, and wherein a distal end surface (11a4) of the ultrasound transducer is formed of a convex curved surface, characterized in that the ultrasound transducer as the transmission and reception member is held by the housing with a back surface side on which a support member is disposed accommodated in a recess and the ultrasound transducer is supported on a bottom surface of the recess. a sheath configured to be inserted into a living body; a drive shaft rotatable in the sheath; and an imaging core portion attached to the drive shaft in the sheath, wherein the imaging core portion includes: a transmission and reception member capable of transmitting and receiving a signal; and a housing holding the transmission and reception member, wherein a side surface of the housing that faces a radial direction of the sheath includes an inclined portion that is inclined to approach a central axis line of the drive shaft toward a distal side until reaching a distal end, wherein the inclined portion extends from a proximal side of a distal end (11a2) of the transmission and reception member to a distal side of the distal end (11a2) of the transmission and reception member, wherein the transmission and reception member are an ultrasound transducer capable of transmitting and receiving ultrasound on a ultrasound transmission and reception surface, and wherein a distal end surface (11a4) of the ultrasound transducer is formed of a convex curved surface, characterized in that the ultrasound transducer as the transmission and reception member is held by the housing with a back surface side on which a support member is disposed accommodated in a recess and the ultrasound transducer is supported on a bottom surface of the recess. a transmission and reception member capable of transmitting and receiving a signal; and a housing holding the transmission and reception member, wherein a side surface of the housing that faces a radial direction of the sheath includes an inclined portion that is inclined to approach a central axis line of the drive shaft toward a distal side until reaching a distal end, wherein the inclined portion extends from a proximal side of a distal end (11a2) of the transmission and reception member to a distal side of the distal end (11a2) of the transmission and reception member, wherein the transmission and reception member are an ultrasound transducer capable of transmitting and receiving ultrasound on a ultrasound transmission and reception surface, and wherein a distal end surface (11a4) of the ultrasound transducer is formed of a convex curved surface, characterized in that the ultrasound transducer as the transmission and reception member is held by the housing with a back surface side on which a support member is disposed accommodated in a recess and the ultrasound transducer is supported on a bottom surface of the recess.